def find_longest_match(self, alo, ahi, blo, bhi):
        """Find longest matching block in a[alo:ahi] and b[blo:bhi].

        Wrapper for the C implementation of this function.
        """
        besti, bestj, bestsize = _cdifflib.find_longest_match(self, alo, ahi, blo, bhi)
        return _Match(besti, bestj, bestsize)