Location of the documentation

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.combine.html

Documentation problem

The fourth example states:

However, if the same element in both dataframes is None, that None is preserved

In the code sample to illustrate this, however, None is not preserved:

df1 = pd.DataFrame({'A': [0, 0], 'B': [None, 4]})
df2 = pd.DataFrame({'A': [1, 1], 'B': [None, 3]})
df1.combine(df2, take_smaller, fill_value=-5)
    A    B
0  0 -5.0
1  0  3.0

Suggested fix for documentation

If the actual result is the intended behavior, this code sample should be removed. If None should indeed be preserved (but why should it?) then this should be filed as a bug.