def _check_frameRange(self, test, expect):
        f = FrameSet(test)
        # the empty FrameSet always has a frameRange of ''
        if not test and not expect:
            self.assertEqual(f.frameRange(), '')
            return
        m = u'FrameSet("{0}").frameRange({1}) != "{2}": got "{3}"'
        p = '((?<![xy:])\d+)'
        l = max([max([len(i) for i in re.findall(p, str(f))]) + 1, 4])
        expect = re.sub(p, lambda m: m.group(0).rjust(l, '0'), str(f))
        try:
            r = f.frameRange(l)
        except Exception as err:
            r = repr(err)
        self.assertEqual(r, expect, m.format(test, l, expect, r))
        m = u'FrameSet("{0}").frameRange({1}) returns {2}: got {3}'
        self.assertIsInstance(r, str, m.format(test, i, str, type(r)))
Harness to test if the FrameSet.frameRange call works properly.
dataset/ETHPy150Open sqlboy/fileseq/test/run.py/TestFrameSet._check_frameRange