condition out_inds >= 0 and condition in_inds >=0 in function create_graph_data

[zjuchenlong]

@danfeiX Hi, recently I read your code and I am confused about the line 31 in function create_graph_data, why condition out_ids >= 0 and condition in_inds >=0 should meet at the same time? From the code in line 32 and 33, it seems like you wanna use or instead of and.