code: def direct_dispatch(self, arg, callback):
          
  
          try:
              self._current_callbacks.appendleft(callback)
  
              exc_info = None
              retval = None
  
              retval = self._routine(arg)
          except:  # pylint:disable=bare-except;We need to capture the exception and feed it back to the caller
              exc_info = sys.exc_info()
          finally:
              self._current_callbacks.popleft()
  
          if callback is not None and retval is not self.STILL_PENDING:
              callback(exc_info, retval)
  
          return retval, exc_info
docs: Directly dispatch a work item.
  
          This method MUST only be called from inside of another work item and
          will synchronously invoke the work item as if it was passed to
          dispatch().  Calling this method from any other thread has undefined
          consequences since it will be unsynchronized with respect to items
          dispatched from inside the background work queue itself.