我尝试了以下贝宝代码，但它没有显示贝宝稍后按钮。是否有任何条件或仅显示美国地理位置

// Loop over each funding source / payment method
paypal_sdk.getFundingSources().forEach(function(fundingSource) {

    // Initialize the buttons
    var button = paypal_sdk.Buttons({
        fundingSource: fundingSource
    });

    // Check if the button is eligible
    if (button.isEligible()) {

        // Render the standalone button for that funding source
        button.render('#paypal-button-container');
    }
});