docs: def _send_command(self, command):
          """Wrapper for self.device.send.command().
  
          If command is a list will iterate through commands until valid command.
          """
          try:
              if isinstance(command, list):
                  for cmd in command:
                      output = self.device.send_command(cmd)
                      if "% Invalid" not in output:
                          break
              else:
                  output = self.device.send_command(command)
              return self._send_command_postprocess(output)
          except (socket.error, EOFError) as e:
              raise ConnectionClosedException(str(e))