docs: def _parse_text(v, header_d):
      """ Parses unicode.
  
      Note:
          unicode types for py2 and str types for py3.
  
      """
  
      v = nullify(v)
  
      if v is None:
          return None
  
      try:
          return six.text_type(v).strip()
      except Exception as e:
          raise CastingError(six.text_type, header_d, v, str(e))