code: def _pump(self):
          '''
          Attempts to process the next command in the queue if one exists and the
          driver is not currently busy.
          '''
          while (not self._busy) and len(self._queue):
              cmd = self._queue.pop(0)
              self._name = cmd[2]
              try:
                  cmd[0](*cmd[1])
              except Exception as e:
                  self.notify('error', exception=e)
                  if self._debug:
                      traceback.print_exc(f _pump(self):
          '''
          Attempts to process the next command in the queue if one exists and the
          driver is not currently busy.
          '''
          while (not self._busy) and len(self._queue):
              cmd = self._queue.pop(0)
              self._name = cmd[2]
              try:
                  cmd[0](*cmd[1])
              except Exception as e:
                  self.notify('error', exception=e)
                  if self._debug:
                      traceback.print_exc()
docs: Attempts to process the next command in the queue if one exists and the
          driver is not currently busy.