import uuid


def validate_uuid5(uuid_string, permissive=False):
    """Test whether a UUID string is a valid uuid.uuid5"""
    try:
        to_validate = str(uuid_string)
        uuid.UUID(to_validate, version=5)
        return True
    except (TypeError, ValueError):
        if permissive is False:
            raise ValueError('{} is not a UUID5'.format(uuid_string))
        else:
            return False