or None
            Series ordered by values or None if ``inplace=True``.

        See Also
        --------
        Series.sort_index : Sort by the Series indices.
        DataFrame.sort_values : Sort DataFrame by the values along either axis.
        DataFrame.sort_index : Sort DataFrame by indices.

        Examples
        --------
        >>> s = pd.Series([np.nan, 1, 3, 10, 5])
        >>> s
        0     NaN
        1     1.0
        2     3.0
        3     10.0
        4     5.0
        dtype: float64

        Sort values ascending order (default behaviour)

        >>> s.sort_values(ascending=True)
        1     1.0
        2     3.0
        4     5.0
        3    10.0
        0     NaN
        dtype: float64

        Sort values descending order

        >>> s.sort_values(ascending=False)
        3    10.0
        4     5.0
        2     3.0
        1     1.0
        0     NaN
        dtype: float64

        Sort values putting NAs first

        >>> s.sort_values(na_position='first')
        0     NaN
        1     1.0
        2     3.0
        4     5.0
        3    10.0
        dtype: float64

        Sort a series of strings

        >>> s = pd.Series(['z', 'b', 'd', 'a', 'c'])
        >>> s
        0    z
        1    b
        2    d
        3    a
        4    c
        dtype: object

        >>> s.sort_values()
        3    a
        1    b
        4    c
        2    d
        0    z
        dtype: object

        Sort using a key function. Your `key` function will be
        given the ``Series`` of values and should return an array-like.

        >>> s = pd.Series(['a', 'B', 'c', 'D', 'e'])
        >>> s.sort_values()
        1    B
        3    D
        0    a
        2    c
        4    e
        dtype: object
        >>> s.sort_values(key=lambda x: x.str.lower())
        0    a
        1    B
        2    c
        3    D
        4    e
        dtype: object

        NumPy ufuncs work well here. For example, we can
        sort by the ``sin`` of the value

        >>> s = pd.Series([-4, -2, 0, 2, 4])
        >>> s.sort_values(key=np.sin)
        1   -2
        4    4
        2    0
        0   -4
        3    2
        dtype: int64

        More complicated user-defined functions can be used,
        as long as they expect a Series and return an array-like

        >>> s.sort_values(key=lambda x: (np.tan(x.cumsum())))
        0   -4
        3    2
        4    4
        1   -2
        2    0
        dtype: int64
        rŒ