def list_to_comma_separated(items: list[str]) -> str:

"""Given a list of items, returns a comma separated string of the items"""

return ",".join(items)

def comma_separated_to_list(comma_separated: str) -> list[str]:

"""Given a comma separated string, returns a list of the comma separated items.

Strips whitespace from each item, drops any items that are whitespace only

"""

items = comma_separated.split(",") if comma_separated else []

non_empty_items = [item.strip() for item in items if item.strip()]

return non_empty_items

def comma_separated_to_set(comma_separated: str) -> set[str]:

"""Given a comma separated string, returns a set of the comma separated items.

Strips whitespace from each item, drops any items that are whitespace only

"""

items = comma_separated.split(",") if comma_separated else []

non_empty_items = {item.strip() for item in items if item.strip()}

return non_empty_items