ex4 to maturity

 
How do you make the " ex4 " used for a predetermined time " X " ?
 

maybe:

datetime end=D'2017.01.01 00:00';

if(end <= TimeCurrent(){
    Alert("END OF LICENSE");
    ExpertRemove();
}
 
tanks
 
 
Alexey, is there some way developer can set these properties in code that is not distributed through MQL5.com market?
Reason: