Retrieve a list of all results associated with the given parameters.

        :param ps: the parameters
        :returns: a list of results, which may be empty

def resultsFor( self, ps ):
        """Retrieve a list of all results associated with the given parameters.

        :param ps: the parameters
        :returns: a list of results, which may be empty"""
        k = self._parametersAsIndex(ps)
        if k in self._results.keys():
            # filter out pending job ids, which can be anything except dicts
            return [ res for res in self._results[k] if isinstance(res, dict) ]
        else:
            return []