the following error occurred while using the mailchimp-api interface to update the mail template. The interface used is patch
The code in the program is as follows: 
 public function actionUpdate () {
    $tid = 48217;
    $arg = [
        "name"=> "Untitled Template",
        "html"=> "<div style="width: 700px"></div>"
    ];
    $apiKey = Yii::$app->params["apiKey"];
    $api_endpoint = Yii::$app->params["api_endpoint"];
    $MailChimp = new MailChimp($apiKey,$api_endpoint);
    $res = $MailChimp->patch("templates/".$tid);
    echo "";
    print_r($res);
}
Please take a look at the problem
.