public void Execute(CustomerBase customerBase)
 {
     if (!customerBase.InformativeMessageIsSent)
     {
         customerBase.InformativeMessageIsSent = true;
     }
     else
     {
         this.nextSubscriptionEvent.Execute(customerBase);
     }
 }
 public void Execute(CustomerBase customerBase)
 {
     if (customerBase.Billed <= 0)
     {
         customerBase.Billed = 6;
     }
     else
     {
         this.nextSubscriptionEvent.Execute(customerBase);
     }
 }
 public void Execute(CustomerBase customerBase)
 {
     if (!customerBase.IsActive)
     {
         customerBase.IsActive = true;
     }
     else
     {
         //it's possible to implement a check, for example go on next one only if the user is active in this case
         this.nextSubscriptionEvent.Execute(customerBase);
     }
 }