def ER(self,*args,**kwargs):
        """
        NAME:

           ER

        PURPOSE:

           calculate the radial energy

        INPUT:

           t - (optional) time at which to get the radial energy (can be Quantity)

           pot= Potential instance or list of such instances

           vo= (Object-wide default) physical scale for velocities to use to convert (can be Quantity)

           use_physical= use to override Object-wide default for using a physical scale for output (can be Quantity)

        OUTPUT:

           radial energy

        HISTORY:

           2013-11-30 - Written - Bovy (IAS)

        """
        if not kwargs.get('pot',None) is None: kwargs['pot']= flatten_potential(kwargs.get('pot'))
        _check_consistent_units(self,kwargs.get('pot',None))
        return self._orb.ER(*args,**kwargs)
NAME:

           ER

        PURPOSE:

           calculate the radial energy

        INPUT:

           t - (optional) time at which to get the radial energy (can be Quantity)

           pot= Potential instance or list of such instances

           vo= (Object-wide default) physical scale for velocities to use to convert (can be Quantity)

           use_physical= use to override Object-wide default for using a physical scale for output (can be Quantity)

        OUTPUT:

           radial energy

        HISTORY:

           2013-11-30 - Written - Bovy (IAS)