I need to add a handling fee to products in a Woocommerce store, but I don’t want it to add the fee if the only items in the cart are virtual/downloadable.

This is what I have so far, but it adds the fee to any order.

// Hook to add a handling fee

add_action( 'woocommerce_cart_calculate_fees','wpcover_handling_fee' );
function wpcover_handling_fee() {
     global $woocommerce;
  
     if ( is_admin() && ! defined( 'DOING_AJAX' ) )
          return;
          $subtotal = WC()->cart->get_subtotal();
          //set our subtotal amount
            if($subtotal > 1) {
                //set our fee amount
                $fee = 1.50;
                //you can change the title of the fee as it appears in the cart
                $woocommerce->cart->add_fee( 'Handling', $fee, true, 'standard' );
            }
}