def METHOD_NAME(self):
    try:
        schemas.FeatureFlagSchema(
            flagKey="valid_flag",
            conditions=[
                schemas.FeatureFlagCondition(name="Condition 1", rollout_percentage=50),
                schemas.FeatureFlagCondition(name="Condition 2", rollout_percentage=25)
            ],
            variants=[
                schemas.FeatureFlagVariant(value="Variant 1", rollout_percentage=50),
                schemas.FeatureFlagVariant(value="Variant 2", rollout_percentage=50)
            ]
        )
    except ValidationError:
        assert False, "Valid data should not raise ValidationError"
    try:
        schemas.FeatureFlagSchema()
    except ValidationError as e:
        assert len(e.errors()) == 1
        for error in e.errors():
            assert error["type"] == "value_error.missing"
            assert error["loc"] in [("flagKey",)]
    else:
        assert False, "Invalid data should raise ValidationError"