docs: def set_display_label(self, display_label):
          """Seta a display label.
  
          arg:    display_label (string): the new display label
          raise:  InvalidArgument - ``display_label`` is invalid
          raise:  NoAccess - ``display_label`` cannot be modified
          raise:  NullArgument - ``display_label`` is ``null``
          *compliance: mandatory -- This method must be implemented.*
  
          """
          if self.get_display_label_metadata().is_read_only():
              raise errors.NoAccess()
          if not self._is_valid_string(display_label,
                                       self.get_display_label_metadata()):
              raise errors.InvalidArgument()
          self._my_map['displayLabel']['text'] = display_label