def __init__(self, *args, **kw):
        super(FieldsMatch, self).__init__(*args, **kw)
        if len(self.field_names) < 2:
            raise TypeError('FieldsMatch() requires at least two field names')
dataset/ETHPy150Open formencode/formencode/formencode/validators.py/FieldsMatch.__init__/original