diff --git a/notebooks/beginner/exercises/strings_exercise.ipynb b/notebooks/beginner/exercises/strings_exercise.ipynb
index 38aee8b..4a406a4 100644
--- a/notebooks/beginner/exercises/strings_exercise.ipynb
+++ b/notebooks/beginner/exercises/strings_exercise.ipynb
@@ -10,14 +10,14 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [],
    "source": [
     "original = ' Python strings are COOL! '\n",
-    "lower_cased = original._____\n",
-    "stripped = ____.strip()\n",
-    "stripped_lower_cased = original._____._____"
+    "lower_cased = original.lower()\n",
+    "stripped = original.strip()\n",
+    "stripped_lower_cased = original.lower().strip()"
    ]
   },
   {
@@ -29,7 +29,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {
     "editable": false
    },
@@ -50,7 +50,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {
     "editable": false
    },
@@ -61,12 +61,12 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 4,
    "metadata": {},
    "outputs": [],
    "source": [
     "# Your implementation:\n",
-    "pretty = 'TODO'"
+    "pretty = ugly.strip().title()"
    ]
   },
   {
@@ -78,11 +78,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "metadata": {
     "editable": false
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "pretty: Title Of My New Book\n"
+     ]
+    }
+   ],
    "source": [
     "print('pretty: {}'.format(pretty))\n",
     "assert pretty == 'Title Of My New Book'"
@@ -98,7 +106,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "metadata": {
     "editable": false
    },
@@ -111,25 +119,40 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [],
    "source": [
     "# Your implementation:\n",
-    "sentence = 'TODO'"
+    "sentence = 'Learning {} {} fun{}'.format(language, verb, punctuation)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 9,
    "metadata": {
     "editable": false
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "sentence: Learning Python is fun!\n"
+     ]
+    }
+   ],
    "source": [
     "print('sentence: {}'.format(sentence))\n",
     "assert sentence == 'Learning Python is fun!'"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
@@ -148,7 +171,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.6.8"
   }
  },
  "nbformat": 4,
diff --git a/notebooks/beginner/notebooks/classes.ipynb b/notebooks/beginner/notebooks/classes.ipynb
index b39b340..f9325af 100644
--- a/notebooks/beginner/notebooks/classes.ipynb
+++ b/notebooks/beginner/notebooks/classes.ipynb
@@ -9,7 +9,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -23,9 +23,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "my_instance: <__main__.MyFirstClass object at 0x7fa35c572c88>\n",
+      "type: <class '__main__.MyFirstClass'>\n",
+      "my_instance.name: John Doe\n"
+     ]
+    }
+   ],
    "source": [
     "my_instance = MyFirstClass('John Doe')\n",
     "print('my_instance: {}'.format(my_instance))\n",
@@ -43,9 +53,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Hello Alice!\n"
+     ]
+    }
+   ],
    "source": [
     "alice = MyFirstClass(name='Alice')\n",
     "alice.greet()"
@@ -61,9 +79,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 4,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "creating instance of Example\n",
+      "Now we are inside __init__\n",
+      "instance created\n"
+     ]
+    }
+   ],
    "source": [
     "class Example:\n",
     "    def __init__(self):\n",
@@ -83,9 +111,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "abc 123\n"
+     ]
+    }
+   ],
    "source": [
     "class Example:\n",
     "    def __init__(self, var1, var2):\n",
@@ -110,9 +146,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "This is the string presentation of jack: Person: Jack\n"
+     ]
+    }
+   ],
    "source": [
     "class Person:\n",
     "    def __init__(self, name, age):\n",
@@ -136,9 +180,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 7,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "instance_variable: foo, name: Modified name, description: Just an example of a simple class\n",
+      "instance_variable: bar, name: Modified name, description: Just an example of a simple class\n"
+     ]
+    }
+   ],
    "source": [
     "class Example:\n",
     "    # These are class variables\n",
@@ -180,7 +233,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -204,9 +257,28 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 10,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "15\n"
+     ]
+    },
+    {
+     "ename": "AttributeError",
+     "evalue": "can't set attribute",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-10-39e95cd1a1a9>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m     11\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mexample_person\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mage\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     12\u001b[0m \u001b[0;31m# But not this:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 13\u001b[0;31m \u001b[0mexample_person\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mage\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;36m16\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+      "\u001b[0;31mAttributeError\u001b[0m: can't set attribute"
+     ]
+    }
+   ],
    "source": [
     "class Person:\n",
     "    def __init__(self, age):\n",
@@ -220,7 +292,7 @@
     "# Now you can do this:\n",
     "print(example_person.age)\n",
     "# But not this:\n",
-    "#example_person.age = 16"
+    "# example_person.age = 16"
    ]
   },
   {
@@ -232,9 +304,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Happy bday for 16 years old!\n"
+     ]
+    }
+   ],
    "source": [
     "class Person:\n",
     "    def __init__(self, age):\n",
@@ -261,7 +341,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 12,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -287,9 +367,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 13,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "wof wof\n",
+      "Dog's favorite food is beef\n",
+      "Hello, I am an animal\n",
+      "Cat's favorite food is fish\n"
+     ]
+    }
+   ],
    "source": [
     "dog = Dog()\n",
     "dog.greet()\n",
@@ -299,6 +390,13 @@
     "cat.greet()\n",
     "print(\"Cat's favorite food is {}\".format(cat.favorite_food))"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
@@ -317,7 +415,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.7.0"
   }
  },
  "nbformat": 4,
diff --git a/notebooks/beginner/notebooks/conditionals.ipynb b/notebooks/beginner/notebooks/conditionals.ipynb
index 3850f20..ed4a13e 100644
--- a/notebooks/beginner/notebooks/conditionals.ipynb
+++ b/notebooks/beginner/notebooks/conditionals.ipynb
@@ -23,18 +23,36 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "type of True and False: <class 'bool'>\n"
+     ]
+    }
+   ],
    "source": [
     "print('type of True and False: {}'.format(type(True)))"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0: False, 1: True\n",
+      "empty list: False, list with values: True\n",
+      "empty dict: False, dict with values: True\n"
+     ]
+    }
+   ],
    "source": [
     "print('0: {}, 1: {}'.format(bool(0), bool(1)))\n",
     "print('empty list: {}, list with values: {}'.format(bool([]), bool(['woop'])))\n",
@@ -50,9 +68,26 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1 == 0: False\n",
+      "1 != 0: True\n",
+      "1 > 0: True\n",
+      "1 > 1: False\n",
+      "1 < 0: False\n",
+      "1 < 1: False\n",
+      "1 >= 0: True\n",
+      "1 >= 1: True\n",
+      "1 <= 0: False\n",
+      "1 <= 1: True\n"
+     ]
+    }
+   ],
    "source": [
     "print('1 == 0: {}'.format(1 == 0))\n",
     "print('1 != 0: {}'.format(1 != 0))\n",
@@ -75,9 +110,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 4,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1 <= 2 <= 3: True\n"
+     ]
+    }
+   ],
    "source": [
     "print('1 <= 2 <= 3: {}'.format(1 <= 2 <= 3))"
    ]
@@ -91,7 +134,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -103,9 +146,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Python and java are both cool: False\n",
+      "secret_value and python_is_cool: True\n"
+     ]
+    }
+   ],
    "source": [
     "print('Python and java are both cool: {}'.format(python_is_cool and java_is_cool))\n",
     "print('secret_value and python_is_cool: {}'.format(secret_value and python_is_cool))"
@@ -113,9 +165,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 7,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Python or java is cool: True\n",
+      "1 >= 1.1 or 2 < float(\"1.4\"): False\n"
+     ]
+    }
+   ],
    "source": [
     "print('Python or java is cool: {}'.format(python_is_cool or java_is_cool))\n",
     "print('1 >= 1.1 or 2 < float(\"1.4\"): {}'.format(1 >= 1.1 or 2 < float('1.4')))"
@@ -123,9 +184,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 8,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Java is not cool: True\n"
+     ]
+    }
+   ],
    "source": [
     "print('Java is not cool: {}'.format(not java_is_cool))"
    ]
@@ -139,9 +208,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 9,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "True\n",
+      "False\n"
+     ]
+    }
+   ],
    "source": [
     "print(bool(not java_is_cool or secret_value and  python_is_cool or empty_list))\n",
     "print(bool(not (java_is_cool or secret_value and  python_is_cool or empty_list)))"
@@ -285,7 +363,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.7.0"
   }
  },
  "nbformat": 4,
diff --git a/notebooks/beginner/notebooks/debugging.ipynb b/notebooks/beginner/notebooks/debugging.ipynb
index af2e669..cf05174 100644
--- a/notebooks/beginner/notebooks/debugging.ipynb
+++ b/notebooks/beginner/notebooks/debugging.ipynb
@@ -103,7 +103,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.7.0"
   }
  },
  "nbformat": 4,
diff --git a/notebooks/beginner/notebooks/dictionaries.ipynb b/notebooks/beginner/notebooks/dictionaries.ipynb
index f1b4f39..f3ab8e9 100644
--- a/notebooks/beginner/notebooks/dictionaries.ipynb
+++ b/notebooks/beginner/notebooks/dictionaries.ipynb
@@ -10,9 +10,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "dict: {}, type: <class 'dict'>\n"
+     ]
+    }
+   ],
    "source": [
     "my_empty_dict = {}  # alternative: my_empty_dict = dict()\n",
     "print('dict: {}, type: {}'.format(my_empty_dict, type(my_empty_dict)))"
@@ -27,9 +35,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 2,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'value1': 1.6, 'value2': 10, 'name': 'John Doe'}\n",
+      "{'value1': 1.6, 'value2': 10, 'name': 'John Doe'}\n",
+      "equal: True\n",
+      "length: 3\n"
+     ]
+    }
+   ],
    "source": [
     "dict1 = {'value1': 1.6, 'value2': 10, 'name': 'John Doe'}\n",
     "dict2 = dict(value1=1.6, value2=10, name='John Doe')\n",
@@ -50,9 +69,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 3,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "keys: dict_keys(['value1', 'value2', 'name'])\n",
+      "values: dict_values([1.6, 10, 'John Doe'])\n",
+      "items: dict_items([('value1', 1.6), ('value2', 10), ('name', 'John Doe')])\n"
+     ]
+    }
+   ],
    "source": [
     "print('keys: {}'.format(dict1.keys()))\n",
     "print('values: {}'.format(dict1.values()))\n",
@@ -68,9 +97,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 4,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'key1': 'new value', 'key2': 99}\n",
+      "value of key1: new value\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {}\n",
     "my_dict['key1'] = 'value1'\n",
@@ -89,7 +127,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -105,9 +143,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 6,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'key1': 'value1', 'key2': 99}\n",
+      "my_key is not in {'key1': 'value1', 'key2': 99}\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {'key1': 'value1', 'key2': 99, 'keyX': 'valueX'}\n",
     "del my_dict['keyX']\n",
@@ -130,9 +177,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 7,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "my_dict: {'ham': 'good', 'carrot': 'super tasty', 'sausage': 'best ever'}\n",
+      "other: {'ham': 'good', 'carrot': 'super tasty', 'sausage': 'best ever'}\n",
+      "equal: True\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {'ham': 'good', 'carrot': 'semi good'}\n",
     "my_other_dict = my_dict\n",
@@ -151,9 +208,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 8,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "my_dict: {'ham': 'good', 'carrot': 'semi good'}\n",
+      "other: {'ham': 'good', 'carrot': 'semi good', 'beer': 'decent'}\n",
+      "equal: False\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {'ham': 'good', 'carrot': 'semi good'}\n",
     "my_other_dict = dict(my_dict)\n",
@@ -173,9 +240,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 9,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "d: None\n",
+      "d: my default value\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {'a': 1, 'b': 2, 'c': 3}\n",
     "d = my_dict.get('d')\n",
@@ -194,9 +270,21 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "dict before pops: {'food': 'ham', 'drink': 'beer', 'sport': 'football'}\n",
+      "food: ham\n",
+      "dict after popping food: {'drink': 'beer', 'sport': 'football'}\n",
+      "food again: default value for food\n",
+      "dict after popping food again: {'drink': 'beer', 'sport': 'football'}\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = dict(food='ham', drink='beer', sport='football')\n",
     "print('dict before pops: {}'.format(my_dict))\n",
@@ -220,9 +308,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 12,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "a: 1\n",
+      "d: my default value\n",
+      "my_dict: {'a': 1, 'b': 2, 'c': 3, 'd': 'my default value'}\n"
+     ]
+    }
+   ],
    "source": [
     "my_dict = {'a': 1, 'b': 2, 'c': 3}\n",
     "a = my_dict.setdefault('a', 'my default value')\n",
@@ -240,9 +338,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 13,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'a': 1, 'b': 2, 'c': 3}\n",
+      "{'a': 1, 'b': 2, 'c': 4}\n"
+     ]
+    }
+   ],
    "source": [
     "dict1 = {'a': 1, 'b': 2}\n",
     "dict2 = {'c': 3}\n",
@@ -271,7 +378,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 14,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -287,13 +394,28 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 10,
    "metadata": {},
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "{'my key': ['Python', 'is', 'still', 'cool']}\n"
+     ]
+    }
+   ],
    "source": [
     "good_dict = {'my key': ['Python', 'is', 'still', 'cool']}\n",
     "print(good_dict)"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
@@ -312,7 +434,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.7.0"
   }
  },
  "nbformat": 4,
diff --git a/notebooks/beginner/notebooks/strings.ipynb b/notebooks/beginner/notebooks/strings.ipynb
index c87bba4..7df87c0 100644
--- a/notebooks/beginner/notebooks/strings.ipynb
+++ b/notebooks/beginner/notebooks/strings.ipynb
@@ -9,7 +9,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -18,27 +18,60 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Python is my favorite programming language!'"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "my_string"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "str"
+      ]
+     },
+     "execution_count": 3,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "type(my_string)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "43"
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "len(my_string)"
    ]
@@ -52,9 +85,20 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Lorem ipsum dolor sit amet, consectetur adipiscing elit.Pellentesque eget tincidunt felis. Ut ac vestibulum est.In sed ipsum sit amet sapien scelerisque bibendum. Sed sagittis purus eu diam fermentum pellentesque.'"
+      ]
+     },
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "long_story = ('Lorem ipsum dolor sit amet, consectetur adipiscing elit.' \n",
     "              'Pellentesque eget tincidunt felis. Ut ac vestibulum est.' \n",
@@ -79,9 +123,25 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Help on method_descriptor:\n",
+      "\n",
+      "replace(...)\n",
+      "    S.replace(old, new[, count]) -> str\n",
+      "    \n",
+      "    Return a copy of S with all occurrences of substring\n",
+      "    old replaced by new.  If the optional argument count is\n",
+      "    given, only the first count occurrences are replaced.\n",
+      "\n"
+     ]
+    }
+   ],
    "source": [
     "help(str.replace)"
    ]
@@ -95,9 +155,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Python is my favorite programming language!\n"
+     ]
+    }
+   ],
    "source": [
     "my_string.replace('a', '?')\n",
     "print(my_string)"
@@ -112,9 +180,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Python will be my favorite programming language!\n"
+     ]
+    }
+   ],
    "source": [
     "my_modified_string = my_string.replace('is', 'will be')\n",
     "print(my_modified_string)"
@@ -129,9 +205,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Python is cool\n"
+     ]
+    }
+   ],
    "source": [
     "secret = '{} is cool'.format('Python')\n",
     "print(secret)"
@@ -139,9 +223,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "My name is John Doe, you can call me John.\n",
+      "My name is John Doe, you can call me John.\n"
+     ]
+    }
+   ],
    "source": [
     "print('My name is {} {}, you can call me {}.'.format('John', 'Doe', 'John'))\n",
     "# is the same as:\n",
@@ -157,7 +250,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -169,9 +262,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 12,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Some cool python libraries: pandas, numpy, requests\n"
+     ]
+    }
+   ],
    "source": [
     "print('Some cool python libraries: {}'.format(cool_python_libs))"
    ]
@@ -185,9 +286,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 13,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Some cool python libraries: pandas, numpy, requests\n",
+      "Some cool python libraries: pandas, numpy, requests\n"
+     ]
+    }
+   ],
    "source": [
     "cool_python_libs = pandas + ', ' + numpy + ', ' + requests\n",
     "print('Some cool python libraries: {}'.format(cool_python_libs))\n",
@@ -207,7 +317,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 14,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -216,27 +326,60 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 15,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'PYTHON HACKER'"
+      ]
+     },
+     "execution_count": 15,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "mixed_case.upper()"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 16,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'python hacker'"
+      ]
+     },
+     "execution_count": 16,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "mixed_case.lower()"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 17,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Python Hacker'"
+      ]
+     },
+     "execution_count": 17,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "mixed_case.title()"
    ]
@@ -250,9 +393,19 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 18,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "ugly:  \n",
+      " \t Some story to tell \n",
+      "stripped: Some story to tell\n"
+     ]
+    }
+   ],
    "source": [
     "ugly_formatted = ' \\n \\t Some story to tell '\n",
     "stripped = ugly_formatted.strip()\n",
@@ -270,9 +423,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 19,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['three', 'different', 'words']\n"
+     ]
+    }
+   ],
    "source": [
     "sentence = 'three different words'\n",
     "words = sentence.split()\n",
@@ -281,18 +442,37 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 20,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "list"
+      ]
+     },
+     "execution_count": 20,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "type(words)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 21,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "['01001', '101101', '11100000']\n"
+     ]
+    }
+   ],
    "source": [
     "secret_binary_data = '01001,101101,11100000'\n",
     "binaries = secret_binary_data.split(',')\n",
@@ -308,9 +488,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 22,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "this looks good\n"
+     ]
+    }
+   ],
    "source": [
     "ugly_mixed_case = '   ThIS LooKs BAd '\n",
     "pretty = ugly_mixed_case.strip().lower().replace('bad', 'good')\n",
@@ -326,9 +514,17 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 23,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "this looks bad\n"
+     ]
+    }
+   ],
    "source": [
     "pretty = ugly_mixed_case.replace('bad', 'good').strip().lower()\n",
     "print(pretty)"
@@ -343,9 +539,18 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 24,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "First line\n",
+      "Second line\n"
+     ]
+    }
+   ],
    "source": [
     "two_lines = 'First line\\nSecond line'\n",
     "print(two_lines)"
@@ -353,13 +558,63 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
+   "execution_count": 25,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "\tThis will be indented\n"
+     ]
+    }
+   ],
    "source": [
     "indented = '\\tThis will be indented'\n",
     "print(indented)"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Conclusion\n",
+    "* new to me:writing long string: \n",
+    "s =('a'\n",
+    "    'b'\n",
+    "    'c')\n",
+    "* 首字母大写\n",
+    "str.title()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\r\n",
+      "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\r\n",
+      "           [-F configfile] [-I pkcs11] [-i identity_file] [-L address]\r\n",
+      "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\r\n",
+      "           [-Q query_option] [-R address] [-S ctl_path] [-W host:port]\r\n",
+      "           [-w local_tun[:remote_tun]] [user@]hostname [command]\r\n"
+     ]
+    }
+   ],
+   "source": [
+    "!ssh"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
@@ -378,7 +633,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.4"
+   "version": "3.6.8"
   }
  },
  "nbformat": 4,