code: def replace_units(self, units, copy=True):
          
          if copy:
              pot = pycopy.deepcopy(self)
          else:
              pot = self
  
          PotentialBase.__init__(pot,
                                 parameters=self.parameters,
                                 origin=self.origin,
                                 R=self.R,
                                 ndim=self.ndim,
                                 units=units)
  
          return pot
docs: Change the unit system of this potential.
  
          Parameters
          ----------
          units : `~gala.units.UnitSystem`
              Set of non-reducable units that specify (at minimum) the
              length, mass, time, and angle units.
          copy : bool (optional)
              If True, returns a copy, if False, changes this object.