code: def represent_as(self, new_pos, new_vel=None):
          
  
          o = super(Orbit, self).represent_as(new_pos=new_pos, new_vel=new_vel)
          return self.__class__(pos=o.pos,
                                vel=o.vel,
                                hamiltonian=self.hamiltonian)
docs: Represent the position and velocity of the orbit in an alternate
          coordinate system. Supports any of the Astropy coordinates
          representation classes.
  
          Parameters
          ----------
          new_pos : :class:`~astropy.coordinates.BaseRepresentation`
              The type of representation to generate. Must be a class (not an
              instance), or the string name of the representation class.
          new_vel : :class:`~astropy.coordinates.BaseDifferential` (optional)
              Class in which any velocities should be represented. Must be a class
              (not an instance), or the string name of the differential class. If
              None, uses the default differential for the new position class.
  
          Returns
          -------
          new_orbit : `gala.dynamics.Orbit`