def subtreeAt(self, vertexId):

        subtree = DictTree()
        vertexIds = self.subtreeIds(vertexId)
        vertexIds = set(vertexIds)

        for vertexId in vertexIds:
            if vertexId in self.adjacencies.keys():
                subtree.__touchVertex(vertexId)
                subtree.adjacencies[vertexId] = self.adjacencies[vertexId].copy()

        deleteIdList = []

        #Now remove the elements in the adjacencies:
        for vertex1 in subtree.adjacencies.keys():
            for vertex2 in subtree.adjacencies[vertex1].keys():
                if vertex2 not in vertexIds:
                    deleteIdList.append((vertex1, vertex2))

        for vertex1, vertex2 in deleteIdList:         
            del subtree.adjacencies[vertex1][vertex2]
           
        return subtree
Ensure get_queue returns the default queue if non was given.
dataset/ETHPy150Open charanpald/APGL/apgl/graph/DictTree.py/DictTree.subtreeAt--crossover with--dataset/ETHPy150Open Workiva/furious/furious/tests/test_async.py/TestAsync.test_get_default_queue