RequiredBirthDate = StaticWidgetAttribute(True,
                                          field=IBasicPerson['birth_date'])


class RequiredBirthDateValidator(validator.SimpleFieldValidator):

    def validate(self, value):
        # XXX: necessary to make the form field behave as required
        super(RequiredBirthDateValidator, self).validate(value)
        if value is None:
            raise RequiredMissing()


validator.WidgetValidatorDiscriminators(
    RequiredBirthDateValidator,
    field=IBasicPerson['birth_date'])