docs: def str(self):
          """Get Access to string functions.
  
          Returns
          -------
          StringMethods
  
          Examples
          --------
          >>> sr = bl.Series([b' aB ', b'GoOsfrABA'])
          >>> print(sr.str.lower().evaluate())
          <BLANKLINE>
          ---  ---------
            0   ab
            1  goosfraba
  
          """
          if self.dtype.char != 'S':
              raise AttributeError('Can only use .str when data is of type np.bytes_')
  
          from .strings import StringMethods
  
          return StringMethods(self)