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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 _sending_task(self, backend):
 """ Used internally to safely increment `backend`s task count. Returns the overall count of tasks for `backend`. """

        with self.backend_mutex:
            self.backends[backend] += 1
            self.task_counter[backend] += 1
            this_task = self.task_counter[backend]
        return this_task