list.size > 0 changed to !list.isEmpty

We care about if it's empty or not, not about it's size

Mage/src/main/java/mage/abilities/mana/TriggeredManaAbility.java

@@ -97,6 +97,6 @@ public abstract class TriggeredManaAbility extends TriggeredAbilityImpl implemen
      */
     @Override
     public boolean definesMana() {
-        return netMana.size() > 0;
+        return !netMana.isEmpty();
     }
 }