code: def _get (self, timeout):
          
          if timeout is None:
              while self._empty():
                  self.not_empty.wait()
          else:
              if timeout < 0:
                  raise ValueError("'timeout' must be a positive number")
              endtime = _time() + timeout
              while self._empty():
                  remaining = endtime - _time()
                  if remaining <= 0.0:
                      raise Empty()
                  self.not_empty.wait(remaining)
          self.in_progress += 1
          return self.queue.popleft()
docs: Non thread-safe utility function of self.get() doing the real
          work.