def nodeGroupName(self, nodeListToQuery):
        nodeSetToQuery = set(nodeListToQuery)
        if nodeSetToQuery not in self.nodeGroupDict.values():
            return None
        for key in self.nodeGroupDict:
            if self.nodeGroupDict[key] == nodeSetToQuery:
                return key
Given a list of nodes, return which group (if any) they represent.
dataset/ETHPy150Open andrew-gardner/dependsworkflow/depends/depends_dag.py/DAG.nodeGroupName