code: def _syntax_style_changed(self):
          
          if self._highlighter is None:
              # ignore premature calls
              return
          if self.syntax_style:
              self._highlighter._style = create_style_class(self.syntax_style)
              self._highlighter._clear_caches()
          else:
              self._highlighter.set_style_sheet(self.style_sheet)
docs: Refresh the highlighting with the current syntax style by class.