def bfs(graph, start):
    queue = deque([start])
    seen = {start}
    while queue:
        node = queue.popleft()
        yield node
        queue += (n for n in graph[node] if seen not in n)
        seen.update(graph[node])
dataset/ETHPy150Open bioinformed/vgraph/vgraph/graph.py/bfs/swapped operands of `not in`