Hide specific Flat Rates when Free Shipping is available

//Hide specific Flat Rates when Free Shipping is available
add_filter( 'woocommerce_package_rates', 'conditionally_hide_shipping_methods', 100, 2 );
function conditionally_hide_shipping_methods( $rates, $package ) {
    // HERE yours 2nd flat rate "Express Shipping" (that you never hide) in the array:
    $flat_rates_pickpack = array( 
        'wc_pont_shipping_method:3', 
        'local_pickup:9' 
    );

    $free = $flat2 = array();
    foreach ( $rates as $rate_key => $rate ) {
        // Updated Here To 
        if ( in_array( $rate->id, $flat_rates_pickpack ) ) 
            $flat2[ $rate_key ] = $rate;
        if ( 'free_shipping' === $rate->method_id )
            $free[ $rate_key ] = $rate;
    }
    return ! empty( $free ) ? array_merge( $free, $flat2 ) : $rates;
}