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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_vrf(self):
 """ List VRFs and return JSON encoded result. """


        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)