<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def span(self):
 """Return a contiguous range that is a superset of this range. Returns: A VersionRange object representing the span of this range. For example, the span of "2+<4|6+<8" would be "2+<8". """

        other = VersionRange(None)
        bound = _Bound(self.bounds[0].lower, self.bounds[-1].upper)
        other.bounds = [bound]
        return other