easyandme

@loiane Hi Loiane. Thank you for this great book! it seems that in the current Graph implementation, one can add duplicate edges to the adjacency list - is this expected?...

@timorthi I got `AttributeError: module '__main__' has no attribute 'add' ` Any thoughts? Many thanks!

@timorthi Sorry! I'd appreciate it if you could take a look at this. I just replaced `foo()` with `add`. The rest of the code is almost the same, except that...

@timorthi Solved. Thank you so much!