def test_no_value(self):
        msg = "'This field is required.'"
        with self.assertRaisesMessage(ValidationError, msg):
            self.field.clean(['some text', ['JP']])
If insufficient data is provided, None is substituted.
dataset/ETHPy150Open django/django/tests/forms_tests/field_tests/test_multivaluefield.py/MultiValueFieldTest.test_no_value