code: def simulationStep(step=0):
      
      global _stepListeners
      responses = _connections[""].simulationStep(step)
      for listener in _stepListeners:
          listener.step(step)
      return responses
docs: Make a simulation step and simulate up to the given millisecond in sim time.
      If the given value is 0 or absent, exactly one step is performed.
      Values smaller than or equal to the current sim time result in no action.