code: def _check_integrate_dt(t,dt):
      
      if dt is None:
          return True
      mult= round((t[1]-t[0])/dt)
      if nu.fabs(mult*dt-t[1]+t[0]) < 10.**-10.:
          return True
      else:
          return False
docs: Check that the stepszie in t is an integer x dt