chore: import upstream snapshot with attribution

easygraph/utils/index_of_node.py

@@ -0,0 +1,12 @@
+__all__ = ["get_relation_of_index_and_node"]
+
+
+def get_relation_of_index_and_node(graph):
+    node2idx = {}
+    idx2node = []
+    node_size = 0
+    for node in graph.nodes:
+        node2idx[node] = node_size
+        idx2node.append(node)
+        node_size += 1
+    return idx2node, node2idx