Problem

stem and plot should be interchangeable.

from matplotlib.pylab import *
style.use(['bmh', 'dark_background'])
a = randn(5)
b = randn(5)

Plotting two lines

plot(a)
plot(b)

Choosing the colours

plot(a, 'r')
plot(b, 'b')

Now with stem

stem(a)
stem(b)

Same colour? Why? Which one is which???

Okay, let me choose the colours

stem(a, 'r')
stem(b, 'b')

ERROR!

Proposed solution

Share the same basic syntax across functions visualising the same type of data?