code: def simulationStep(self, step=0):
          
          self._queue.append(tc.CMD_SIMSTEP)
          self._string += struct.pack("!BBi", 1 +
                                      1 + 4, tc.CMD_SIMSTEP, step)
          result = self._sendExact()
          for subscriptionResults in self._subscriptionMapping.values():
              subscriptionResults.reset()
          numSubs = result.readInt()
          responses = []
          while numSubs > 0:
              responses.append(self._readSubscription(result))
              numSubs -= 1
          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.