Plot two histograms on single chart

Here you have a working example:

import random
import numpy
from matplotlib import pyplot

x = [random.gauss(3,1) for _ in range(400)]
y = [random.gauss(4,2) for _ in range(400)]

bins = numpy.linspace(-10, 10, 100)

pyplot.hist(x, bins, alpha=0.5, label="x")
pyplot.hist(y, bins, alpha=0.5, label="y")
pyplot.legend(loc="upper right")
pyplot.show()