def _patchDatetimeMetadata( self, res, mk ):
t = res[epyc.Experiment.METADATA][mk]<EOL>res[epyc.Experiment.METADATA][mk] = dateutil.parser.parse(t)<EOL>
Private method to patch an ISO datetime string to a datetime object
        for metadata key mk.

        :param res: results dict
        :param mk: metadata key