Change Booking Price

function em_mod_ticket_booking($price, $EM_Ticket_Booking){
 if ( $EM_Ticket_Booking->ticket_booking_spaces > 1 ){
  $price = round( (($EM_Ticket_Booking->get_ticket()->get_price_without_tax() * $EM_Ticket_Booking->ticket_booking_spaces) + 10), 2);
 }
 return $price;
}
add_filter('em_ticket_booking_get_price','em_mod_ticket_booking',1,3);