See https://github.com/satwikkansal/wtfpython

"Mutating the immutable" is my personal favourite - the second line of code fails with an exception despite having already succeeded:

    >>> t = ([1, 2], 5, 6)

    >>> t[0] += [3, 4]
    TypeError: 'tuple' object does not support item assignment

    >>> print(t)
    ([1, 2, 3, 4], 5, 6)

I've never been a fan of the decision to have `a += b` sometimes do `a = a + b` and sometimes update `a` in place. My objection was initially just due to theoretical inelegance - but this code shows that decision directly causing a concrete problem.