Cancel all pending results. Note that this only affects the
        notebook's record, not any job running in a lab.

def cancelAllPendingResults( self ):
        """Cancel all pending results. Note that this only affects the
        notebook's record, not any job running in a lab."""
        for k in self._results.keys():
            rs = self._results[k]
            self._results[k] = [ j for j in rs if isinstance(j, dict) ]
        self._pending = dict()