code: def rguiding(self,*args,**kwargs):
          
          pot= kwargs.get('pot',self._orb.__dict__.get('_pot',None))
          if pot is None:
              raise RuntimeError("You need to specify the potential as pot= to compute the guiding-center radius")
          flatten_potential(pot)
          if _isNonAxi(pot):
              raise RuntimeError('Potential given to rguiding is non-axisymmetric, but rguiding requires an axisymmetric potential')
          _check_consistent_units(self,pot)
          Lz= self.Lz(*args,use_physical=False)
          return nu.array([rl(pot,lz,use_physical=False) for lz in Lz])
docs: NAME:
  
             rguiding
  
          PURPOSE:
  
             calculate the guiding-center radius (the radius of a circular orbit with the same angular momentum)
  
          INPUT:
  
             pot= potential instance or list of such instances
  
             ro= (Object-wide default) physical scale for distances to use to convert (can be Quantity)
  
             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
  
          OUTPUT:
  
             R_guiding
  
          HISTORY:
  
             2018-08-29 - Written as thin wrapper around Potential.rl - Bovy (UofT)