>>> s = pd.Series([1, None, None, 2])
        >>> s.bfill()
        0    1.0
        1    2.0
        2    2.0
        3    2.0
        dtype: float64
        >>> s.bfill(limit=1)
        0    1.0
        1    NaN
        2    2.0
        3    2.0
        dtype: float64

        With DataFrame:

        >>> df = pd.DataFrame({{'A': [1, None, None, 4], 'B': [None, 5, None, 7]}})
        >>> df
              A     B
        0   1.0	  NaN
        1   NaN	  5.0
        2   NaN   NaN
        3   4.0   7.0
        >>> df.bfill()
              A     B
        0   1.0   5.0
        1   4.0   5.0
        2   4.0   7.0
        3   4.0   7.0
        >>> df.bfill(limit=1)
              A     B
        0   1.0   5.0
        1   NaN   5.0
        2   4.0   7.0
        3   4.0   7.0
        rc