graph.py 文件源码

def assert_graph_is_valid(self):
        """Asserts that the graph is valid."""
        assert is_directed_acyclic_graph(self.graph), "Graph is not a DAG."
        for name in self.output_nodes:
            assert self.is_sink_node(name), "Output node {} is not a sink.".format(name)
            assert not self.is_source_node(name), "Output node {} is a source node. " \
                                                  "Make sure it's connected.".format(name)
        for name in self.input_nodes:
            assert self.is_source_node(name), "Input node {} is not a source.".format(name)
            assert not self.is_sink_node(name), "Input node {} is a sink node. " \
                                                "Make sure it's connected.".format(name)