Override default *range= handler to account for relative computation.

def _ctorCmprRange(self, vals):
        '''
        Override default *range= handler to account for relative computation.
        '''

        if not isinstance(vals, (list, tuple)):
            raise s_exc.BadCmprValu(valu=vals, cmpr='*range=')

        if len(vals) != 2:
            raise s_exc.BadCmprValu(valu=vals, cmpr='*range=')

        tick, tock = self.getTickTock(vals)

        if tick > tock:
            # User input has requested a nullset
            def cmpr(valu):
                return False

            return cmpr

        def cmpr(valu):
            return tick <= valu <= tock

        return cmpr