 extension RGAppTools where Base: UserDefaults {
 
     /// 检验 UserDefaults 中是否存在某个 key
+    /// ```
+    /// // How to use
+    /// UserDefaults.standard.rat.has(Key<TypeName>("key"))
+    /// ```
     /// - Parameter key: 待检验的 key
     /// - Returns: 检验结果
     public func has<ValueType>(_ key: Key<ValueType>) -> Bool {

    /// - Returns: 检验结果
    private func isPrimitive<ValueType>(type: ValueType.Type) -> Bool {
        switch type {
        case is String.Type, is Bool.Type, is Int.Type, is Float.Type, is Double.Type:
            return true
        default:
            return false
        }
    }


    }

    /// 获取 key 值对应的内容
    /// ```
    /// // How to use
    /// UserDefaults.standard.rat.value(Key<TypeName>("key"))
    /// ```
    /// - Parameter key: 标记内容的 key
    /// - Returns: key 对应的内容
    public func value<ValueType>(for key: Key<ValueType>) -> ValueType? {
