diff --git a/2/interfaces.md b/2/interfaces.md
index 6805ad0..6c9a742 100644
--- a/2/interfaces.md
+++ b/2/interfaces.md
@@ -54,7 +54,7 @@ interface Car:
     def payForPetrol(): payable
 
 @external
-def test(some_address: address):
+def test(car_address: address):
     Car(car_address).calculateDoubleSpeed()  # cannot change storage
     Car(car_address).getSpeed()  # cannot change storage, but reads itself
     Car(car_address).increaseSpeed()  # storage can be altered