如何通过现有客户的电子邮件地址检索其标识符，或者如果客户在使用API Stripe创建付款时毫不犹豫地创建客户？
我在Stripe文档中进行了搜索，但没有找到答案。

require "Stripe/vendor/autoload.php";

// This is your test secret API key.
\Stripe\Stripe::setApiKey("sk_test_XXX");

header("Content-Type: application/json");

try {
    // retrieve JSON from POST body
    $jsonStr = file_get_contents("php://input");
    $jsonObj = json_decode($jsonStr);

    // get customer if exist
    $query = \Stripe\Customer::search([
        "query" => 'email:\'.'.$user['email'].'.\'', 
    ]);
    
    if ($query->id) {
        $customer_ID = $query->id;
    } else {
        $customer = \Stripe\Customer::create([
            "email" => $user["email"],
            "description" => 'VIP plan',
        ]);
        
        $customer_ID = $customer->id;
    }


    // Create a PaymentIntent with amount and currency
    $paymentIntent = \Stripe\PaymentIntent::create([
        "customer" => $customer_ID,
        "amount" => 1400,
        "currency" => "usd",
        "automatic_payment_methods" => [
            "enabled" => true,
        ],
    ]);

    $output = [
        "clientSecret" => $paymentIntent->client_secret,
    ];

    echo json_encode($output);
} catch (Error $e) {
    http_response_code(500);
    echo json_encode(["error" => $e->getMessage()]);
}