def _filter_mod(self, mod, magicstr, checkstr=None):
        """ helper function to filter out modules by name"""
        filt = [x for x in mod if magicstr in x.name]
        if checkstr is not None:
            for x in filt:
                assert checkstr in str(x)
        return filt
 helper function to filter out modules by name
numba/tests/test_parfors.py