code: def initialize_time(self, control_freq):
          
          self.cur_time = 0
          self.model_timestep = self.sim.model.opt.timestep
          if self.model_timestep <= 0:
              raise XMLError("xml model defined non-positive time step")
          self.control_freq = control_freq
          if control_freq <= 0:
              raise SimulationError(
                  "control frequency {} is invalid".format(control_freq)
              )
          self.control_timestep = 1. / control_freq
docs: Initializes the time constants used for simulation.