df = pd.DataFrame({  # doctest: +SKIP
    'length': [1.5, 0.5, 1.2, 0.9, 3],
    'width': [0.7, 0.2, 0.15, 0.2, 1.1]
    }, index=['pig', 'rabbit', 'duck', 'chicken', 'horse'])
hist = df.hist(bins=3)  # doctest: +SKIP