Turn-off Auto Approved Offline Payment

<?php

/*
 This snippet will auto approved Offline Payment Gateway
 */
function my_offline_turnoff_auto_approve_filter( $result, $EM_Booking ){
  if( $EM_Booking->booking_meta['gateway'] == 'offline'  ){
    $EM_Booking->set_status(1,false);
  }
  return $result;
}
add_filter('em_booking_save', 'my_offline_turnoff_auto_approve_filter', 100, 2);