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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def worker_channels(self):
 """ Access the worker_channels :returns: twilio.rest.taskrouter.v1.workspace.worker.worker_channel.WorkerChannelList :rtype: twilio.rest.taskrouter.v1.workspace.worker.worker_channel.WorkerChannelList """

        if self._worker_channels is None:
            self._worker_channels = WorkerChannelList(
                self._version,
                workspace_sid=self._solution['workspace_sid'],
                worker_sid=self._solution['sid'],
            )
        return self._worker_channels