limit bookings to 1 ticket only

/**
 * if ( $EM_Booking->booking_spaces > 2){ echo "Max of 2 ticket spacess is allowed"; }
 */
function my_em_booking_ticket($result,$EM_Booking){

  $ticket_count = 0;

  foreach($EM_Booking->tickets_bookings as $EM_Ticket_Booking){
  	$ticket_count++;
  }

  if ( $ticket_count > 1 ){
  	$EM_Booking->add_error('Only one ticket is allowed per booking');
  	$result = false;
  }

  return $result;
}
add_filter('em_booking_validate','my_em_booking_ticket',100,2);