Not able to customise font sizes on the dropdown

Hi! I am using the code below to customise change the sizes on the font dropdown.

// Customize mce editor font sizes
if ( ! function_exists( ‘wpex_mce_text_sizes’ ) ) {
function wpex_mce_text_sizes( $initArray ){
$initArray[‘fontsize_formats’] = “10px 12px 13px 14px 16px 18px 20px 22px 24px 26px 28px 30px 32px 34px 36px 38px 40px 42px 44px 46px 48px 50px”;
return $initArray;
}
}
add_filter( ‘tiny_mce_before_init’, ‘wpex_mce_text_sizes’, 9999, 1 );

This usually works but unexpectedly didn’t work on one of my websites. I have the plugin installed Advanced Editor Tools Version 5.9.2. I think the hook tiny_mce_before_init is probably not running.

Can you please help me with this please.