Is called if a working event occurred.

        :param int handle: USB-CAN-Handle returned by the function :meth:`init_hardware`.
        :param int event: Event type.
        :param int channel:
            CAN channel (:data:`Channel.CHANNEL_CH0`, :data:`Channel.CHANNEL_CH1` or :data:`Channel.CHANNEL_ANY`).
        :param arg: Additional parameter defined with :meth:`init_hardware_ex`.

def _callback(self, handle, event, channel, arg):
        """
        Is called if a working event occurred.

        :param int handle: USB-CAN-Handle returned by the function :meth:`init_hardware`.
        :param int event: Event type.
        :param int channel:
            CAN channel (:data:`Channel.CHANNEL_CH0`, :data:`Channel.CHANNEL_CH1` or :data:`Channel.CHANNEL_ANY`).
        :param arg: Additional parameter defined with :meth:`init_hardware_ex`.
        """
        log.debug("Handle: %s, Event: %s, Channel: %s" % (handle, event, channel))

        if event == CbEvent.EVENT_INITHW:
            self.init_hw_event()
        elif event == CbEvent.EVENT_init_can:
            self.init_can_event(channel)
        elif event == CbEvent.EVENT_RECEIVE:
            self.can_msg_received_event(channel)
        elif event == CbEvent.EVENT_STATUS:
            self.status_event(channel)
        elif event == CbEvent.EVENT_DEINIT_CAN:
            self.deinit_can_event(channel)
        elif event == CbEvent.EVENT_DEINITHW:
            self.deinit_hw_event()