<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _unsigned_bounds(self):
 """ Get lower bound and upper bound for `self` in unsigned arithmetic. :return: a list of (lower_bound, upper_bound) tuples. """


        ssplit = self._ssplit()
        if len(ssplit) == 1:
            lb = ssplit[0].lower_bound
            ub = ssplit[0].upper_bound

            return [ (lb, ub) ]
        elif len(ssplit) == 2:
            # ssplit[0] is on the left hemisphere, and ssplit[1] is on the right hemisphere

            lb_1 = ssplit[0].lower_bound
            ub_1 = ssplit[0].upper_bound

            lb_2 = ssplit[1].lower_bound
            ub_2 = ssplit[1].upper_bound

            return [ (lb_1, ub_1), (lb_2, ub_2) ]
        else:
            raise Exception('WTF')