type __mul__ is wierd:

>> 'a'.__mul__(3.4)
'aaa'
>>> [1].__mul__(3.4)
[1, 1, 1]

Floating point numbers with fractions should not be
accepted.
I think the problem is that __mul__ should not be trying to
implement sq_repeat behavior (although I haven't dug
deeply into this problem yet).  Also, I think the code is
vulnerable to integer overflow.

Should also check __imul__ __add__ __iadd__.