'''
Given a binary tree, design an algorithm which creats a linked list of all the ndoes at each depth.

If you have a tree with depth D, you'll have D linked lists.

Hints: 107, 123, 135
'''


def lists_of_depth(s):
    pass

if __name__ == '__main__':
    assert lists_of_depth('') ==
    assert lists_of_depth('') ==
    assert lists_of_depth('') ==
    assert lists_of_depth('') ==
    assert lists_of_depth('') ==
