Unable to change the Price Unit options

I tried adding the snippet from your website for changing the price units, but unfortunately, i am failing for that.

Created a child theme, and added the following to the child function.php


add_filter( 'rtcl_get_price_unit_list', function ( $unit_list ){
	$unit_list['katha'] = [
		'title' => esc_html__("Katha", 'classima'),
		'short' => esc_html__("Per Katha", 'classima')
	];

	return $unit_list;
});

Please help!

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