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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 _pop(self, block=True, timeout=None, left=False):
 """Removes and returns the an item from this GeventDeque. This is an internal method, called by the public methods pop() and popleft(). """

        item  = None
        timer = None
        deque = self._deque
        empty = IndexError('pop from an empty deque')

        if block is False:
            if len(self._deque) > 0:
                item = deque.popleft() if left else deque.pop()
            else:
                raise empty
        else:
            try:
                if timeout is not None:
                    timer = gevent.Timeout(timeout, empty)
                    timer.start()

                while True:
                    self.notEmpty.wait()
                    if len(deque) > 0:
                        item = deque.popleft() if left else deque.pop()
                        break
            finally:
                if timer is not None:
                    timer.cancel()

        if len(deque) == 0:
            self.notEmpty.clear()

        return item