docs: def _request(self):
          """ Requests a checking of the editor content. """
          try:
              self.editor.toPlainText()
          except (TypeError, RuntimeError):
              return
          try:
              max_line_length = self.editor.modes.get(
                  'RightMarginMode').position
          except KeyError:
              max_line_length = 79
          request_data = {
              'code': self.editor.toPlainText(),
              'path': self.editor.file.path,
              'encoding': self.editor.file.encoding,
              'ignore_rules': self.ignore_rules,
              'max_line_length': max_line_length,
          }
          try:
              self.editor.backend.send_request(
                  self._worker, request_data, on_receive=self._on_work_finished)
              self._finished = False
          except NotRunning:
              # retry later
              QtCore.QTimer.singleShot(100, self._request)