Adding bonus parts.

src/main/java/org/model/ElectricCar.java

@@ -56,4 +56,16 @@ public class ElectricCar extends Car implements Chargeable {
                 chargeLevel += amount;
         }
     }
+
+    @Override
+    public void performService() {
+        super.performService();
+        System.out.println("Electric engine and oil checked");
+        this.chargeLevel = 100;
+    }
+
+    @Override
+    public boolean needsService(Vehicle v) {
+        return getMileage() > 10000;
+    }
 }