code: def reverse(self):
          
          if hasattr(self,'_orbInterp'): delattr(self,'_orbInterp')
          if hasattr(self,'rs'): delattr(self,'rs')
          sortindx = list(range(len(self._orb.t)))
          sortindx.sort(key=lambda x: self._orb.t[x],reverse=True)
          for ii in range(self._orb.orbit.shape[1]):
              self._orb.orbit[:,ii]= self._orb.orbit[sortindx,ii]
          return None
docs: NAME:
  
             reverse
  
          PURPOSE:
  
             reverse an already integrated orbit (that is, make it go from end to beginning in t=0 to tend)
  
          INPUT:
  
             (none)
  
          OUTPUT:
  
             (none)
  
          HISTORY:
             2011-04-13 - Written - Bovy (NYU)