code: def list_vrf(self):
          
  
          try:
              vrfs = VRF.list()
          except NipapError, e:
              return json.dumps({'error': 1, 'message': e.args, 'type': type(e).__name__})
  
          return json.dumps(vrfs, cls=NipapJSONEncoder)
docs: List VRFs and return JSON encoded result.