A Series of booleans indicating whether the given pattern matches
            the start of each string element.

        See Also
        --------
        str.startswith : Python standard library string method.
        Series.str.endswith : Same as startswith, but tests the end of string.
        Series.str.contains : Tests if string element contains a pattern.

        Examples
        --------
        >>> s = pd.Series(['bat', 'Bear', 'cat', np.nan])
        >>> s
        0     bat
        1    Bear
        2     cat
        3     NaN
        dtype: object

        >>> s.str.startswith('b')
        0     True
        1    False
        2    False
        3      NaN
        dtype: object

        >>> s.str.startswith(('b', 'B'))
        0     True
        1     True
        2    False
        3      NaN
        dtype: object

        Specifying `na` to be `False` instead of `NaN`.

        >>> s.str.startswith('b', na=False)
        0     True
        1    False
        2    False
        3    False
        dtype: bool
        ú expected a string or tuple, not ©