def exportValue(self, vf, value):
        m = StrStrHashMap(value)
        keysAndValues = []
        for i in m.keys():
            keysAndValues.append(i)
            keysAndValues.append(m[i])
def __repr__(self):
        return "<differencematcher m1=%r, m2=%r>" % (self._m1, self._m2)