replace local pick up by the shipping id.

hi there i am trying to hide shipping id:3

I found this code from https://www.wpexplorer.com/best-woocommerce-snippets-wordpress/ but I don’t how to make it work.
I want to replace local pick up by the shipping id.

Thank you very much

$method_key_id = 'flat_rate:3';
	
	if ( ! empty( $new_rates ) ) {
		//Save local pickup if it's present.
		foreach ( $rates as $rate_id => $rate ) {
			if ('local_pickup' === $rate->method_id ) {
				$new_rates[ $rate_id ] = $rate;
				break;

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