def validate_engine(engine):
    """
    Validate database Engine for DBInstance
    Property: DBInstance.Engine
    Property: DBCluster.Engine
    """

    VALID_DB_ENGINES = (
        "MySQL",
        "mysql",
        "oracle-se1",
        "oracle-se2",
        "oracle-se",
        "oracle-ee",
        "sqlserver-ee",
        "sqlserver-se",
        "sqlserver-ex",
        "sqlserver-web",
        "postgres",
        "aurora",
        "aurora-mysql",
        "aurora-postgresql",
        "mariadb",
    )

    if engine not in VALID_DB_ENGINES:
        raise ValueError(
            "DBInstance Engine must be one of: %s" % ", ".join(VALID_DB_ENGINES)
        )
    return engine