Wrapper for self.device.send.command().

        If command is a list will iterate through commands until valid command.

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))