code: def unicode(self, b, encoding=None):
          
          if encoding is None:
              encoding = self.string_encoding
  
          # TODO: Wrap UnicodeDecodeErrors with a message about setting
          # the string_encoding and decode_errors attributes.
          return unicode(b, encoding, self.decode_errors)
docs: Convert a byte string to unicode, using string_encoding and decode_errors.
  
          Arguments:
  
            b: a byte string.
  
            encoding: the name of an encoding.  Defaults to the string_encoding
              attribute for this instance.
  
          Raises:
  
            TypeError: Because this method calls Python's built-in unicode()
              function, this method raises the following exception if the
              given string is already unicode:
  
                TypeError: decoding Unicode is not supported