code: def _parse_ergodic_cutoff(self):
          
          ec_is_str = isinstance(self.ergodic_cutoff, str)
          if ec_is_str and self.ergodic_cutoff.lower() == 'on':
              if self.sliding_window:
                  return 1.0 / self.lag_time
              else:
                  return 1.0
          elif ec_is_str and self.ergodic_cutoff.lower() == 'off':
              return 0.0
          else:
              return self.ergodic_cutoff
docs: Get a numeric value from the ergodic_cutoff input,
          which can be 'on' or 'off'.