code: def nemo_accpars(self,vo,ro):
          
          try:
              return self._nemo_accpars(vo,ro)
          except AttributeError:
              raise AttributeError('NEMO acceleration parameters not supported for %s' % self.__class__.__name__)
docs: NAME:
  
             nemo_accpars
  
          PURPOSE:
  
             return the accpars potential parameters for use of this potential with NEMO
  
          INPUT:
  
             vo - velocity unit in km/s
  
             ro - length unit in kpc
  
          OUTPUT:
  
             accpars string
  
          HISTORY:
  
             2014-12-18 - Written - Bovy (IAS)