【Unity】System.Action 呼び出し時の null チェックを省略する

using System;
/// <summary>
/// Action拡張メソッド
/// </summary>
public static class ActionExtensions
{
    /// <summary>
    /// Action呼び出し。
    /// </summary>
    static public void Call( this Action self )
    {
        if(self != null)
        {
            self();
        }
    }
    /// <summary>
    /// Action呼び出し(引数１つ)
    /// </summary>
    public static void Call<T>( this Action<T> self, T arg )
    {
        if(self != null)
        {
            self(arg);
        }
    }
    /// <summary>
    /// Action呼び出し(引数２つ)
    /// </summary>
    public static void Call<T1, T2>( this Action<T1, T2> self, T1 arg1, T2 arg2 )
    {
        if(self != null)
        {
            self(arg1, arg2);
        }
    }
    /// <summary>
    /// Action呼び出し(引数３つ)
    /// </summary>
    public static void Call<T1, T2, T3>( this Action<T1, T2, T3> self, T1 arg1, T2 arg2, T3 arg3 )
    {
        if (self != null)
        {
            self(arg1, arg2, arg3);
        }
    }
    /// <summary>
    /// Func呼び出し
    /// </summary>
    public static TResult Call<TResult>(this Func<TResult> self, TResult result = default(TResult))
    {
        return self != null ? self() : result;
    }
    /// <summary>
    /// Func呼び出し(引数１つ)
    /// </summary>
    public static TResult Call<T, TResult>(this Func<T, TResult> self, T arg, TResult result = default(TResult))
    {
        return self != null ? self(arg) : result;
    }
    /// <summary>
    /// Func呼び出し(引数２つ)
    /// </summary>
    public static TResult Call<T1, T2, TResult>(this Func<T1, T2, TResult> self, T1 arg1, T2 arg2, TResult result = default(TResult))
    {
        return self != null ? self(arg1, arg2) : result;
    }
    /// <summary>
    /// Func呼び出し(引数３つ)
    /// </summary>
    public static TResult Call<T1, T2, T3, TResult>(this Func<T1, T2, T3, TResult> self, T1 arg1, T2 arg2, T3 arg3, TResult result = default(TResult))
    {
        return self != null ? self(arg1, arg2, arg3) : result;
    }
    /// <summary>
    /// 存在チェックチェック。
    /// </summary>
    static public bool HasAction( this Action self )
    {
        return (self != null) ? true : false;
    }
}

System.Action action = null;
action.call(); // 個々で null チェックせずに済む。