Implementation of bfs_nodes now uses bfs_edges

dace/sdfg/graph.py

@@ -364,7 +364,7 @@ def sink_nodes(self) -> List[NodeT]:
         """Returns nodes with no outgoing edges."""
         return [n for n in self.nodes() if self.out_degree(n) == 0]
 
-    def bfs_nodes(self, source: NodeT = None) -> Sequence[NodeT]:
+    def bfs_nodes(self, source: NodeT = None) -> Iterable[NodeT]:
         """Returns nodes in topological order iff the graph contains exactly
         one node with no incoming edges."""
         if source is not None:
@@ -375,17 +375,9 @@ def bfs_nodes(self, source: NodeT = None) -> Sequence[NodeT]:
                 sources = [self.nodes()[0]]
             if len(sources) > 1:
                 sources = [self.nodes()[0]]
-        seen = OrderedDict()  # No OrderedSet in Python
-        queue = deque(sources)
-        while len(queue) > 0:
-            node = queue.popleft()
-            seen[node] = None
-            for e in self.out_edges(node):
-                succ = e.dst
-                if succ not in seen:
-                    seen[succ] = None
-                    queue.append(succ)
-        return seen.keys()
+
+        for edge in self.bfs_edges(sources):
+            yield edge.src
 
     def all_simple_paths(self,
                          source_node: NodeT,