Python with matplotlib - reusing drawing functions

Here you want to use the Artist objects, and pass them as needed to the functions:

import numpy as np
import matplotlib.pyplot as plt

def myhist(ax, color):
    ax.hist(np.log(np.arange(1, 10, .1)), facecolor=color)

def say_something(ax, words):
    t = ax.text(.2, 20., words)
    make_a_dim_yellow_bbox(t)

def make_a_dim_yellow_bbox(txt):
    txt.set_bbox(dict(facecolor='yellow', alpha=.2))

fig = plt.figure()
ax0 = fig.add_subplot(1,2,1)
ax1 = fig.add_subplot(1,2,2)

myhist(ax0, 'blue')
myhist(ax1, 'green')

say_something(ax0, 'this is the blue plot')
say_something(ax1, 'this is the green plot')

plt.show()