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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 addPendingResult( self, ps, jobid ):
 """Add a "pending" result that we expect to get results for. :param ps: the parameters for the result :param jobid: an identifier for the pending result"""

        k = self._parametersAsIndex(ps)

        # retrieve or create the result list
        if k in self._results.keys():
            rs = self._results[k]
        else:
            rs = []
            self._results[k] = rs

        # append the pending result's jobid
        rs.insert(0, jobid)

        # map job id to parameters to which it refers
        self._pending[jobid] = k