Disable 'Flat Rate' shipping method when 'Weight Country' is available in cart

Hello,

I hope someone could help about the below issue.

I try to adapt the below function but it seems that it does not work:

/**
 * woocommerce_package_rates is a 2.1+ hook
 */
add_filter( 'woocommerce_package_rates', 'hide_flat_rate_when_wf_country_weight_woocommerce_shipping_is_available', 10, 2 );

/**
 * Hide flat rate when country weight shipping is available
 *
 * @param array $rates Array of rates found for the package
 * @param array $package The package array/object being shipped
 * @return array of modified rates
 */
function hide_flat_rate_when_wf_country_weight_woocommerce_shipping_is_available( $rates, $package ) {

 	// Only modify rates if free_shipping is present
  	if ( isset( $rates['flat_rate'] ) && isset($rates['wf_country_weight_woocommerce_shipping']) ) {

  		// To unset a single rate/method, do the following. This example unsets flat_rate shipping
  		unset( $rates['flat_rate'] );

	}

		return $rates;
}

When both methods are available for checkout, the ‘Flat Rate’ one has to be hidden.

I use specific shipping classes in the ‘Flat Rate method.

Thank you for your help!!

https://www.ads-software.com/plugins/weight-country-woocommerce-shipping/