code: def to_coord_frame(self, frame, galactocentric_frame=None, **kwargs):
          if self.ndim != 3:
              raise ValueError("Can only change representation for "
                               "ndim=3 instances.")
          if galactocentric_frame is None:
              galactocentric_frame = coord.Galactocentric()
          if 'vcirc' in kwargs or 'vlsr' in kwargs:
              import warnings
              warnings.warn("Instead of passing in 'vcirc' and 'vlsr', specify "
                            "these parameters to the input Galactocentric frame "
                            "using the `galcen_v_sun` argument.",
                            DeprecationWarning)
          pos_keys = list(self.pos_components.keys())
          vel_keys = list(self.vel_components.keys())
          if (getattr(self, pos_keys[0]).unit == u.one or
                  getattr(self, vel_keys[0]).unit == u.one):
              raise u.UnitConversionError("Position and velocity must have "
                                          "dimensioned units to convert to a "
                                          "coordinate frame.")
          gc_c = galactocentric_frame.realize_frame(
              self.pos.with_differentials(self.vel))
          c = gc_c.transform_to(frame)
          return c