def METHOD_NAME():
    x = torch.randn(4, 16)
    edge_index = torch.tensor([[0, 0, 0], [1, 2, 3]])
    row, col = edge_index
    conv = GCNConv(16, 32, flow="source_to_target")
    out1 = conv(x, edge_index)
    conv.flow = "target_to_source"
    out2 = conv(x, edge_index.flip(0))
    assert torch.allclose(out1, out2, atol=1e-6)