def init(cls, typ, class2type):
        """
        Defines custom fields in the value factory so that the importer can find them
        @param typ
        @param class2type
        """
        field = typ.getField(cls.FIELD_NAME)
        class2type.put( StrStrHashMap , typ )
        typ.setComponentType( StrStrHashMap )
        typ.setImportExportHelper( StrStrHashMapSerializer(typ, field))
        typ.putValidator(field, Validator_object.get(1))
        typ.lock()
def expiration_datetime(self):
        """Datetime that the verification will expire. """
        days_good_for = settings.VERIFY_STUDENT["DAYS_GOOD_FOR"]
        return self.created_at + timedelta(days=days_good_for)