'''
Implement a function to check if a binary tree is balanced for the purposes of this question, a balanced tree is defined to be a tree such that the heights of the two subtress of any node never differ by more than one.

Hints: 21, 33, 49, 105, 124
'''


def chk_balanced(s):
    pass

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