update the default case to use a generic message

lib/koans/16_protocols.ex

@@ -6,8 +6,8 @@ defmodule Protocols do
   defprotocol School, do: def enrol(person)
 
   defimpl School, for: Any do
-    def enrol(person) do
-      "#{person.name} enrolled at school"
+    def enrol(_) do
+      "Pupil enrolled at school"
     end
   end
 

test/koans/protocols_koans_test.exs

@@ -5,7 +5,7 @@ defmodule ProtocolsTests do
   test "Protocols" do
     answers = [
       {:multiple, ["Andre signed up for violin", "Darcy enrolled for ballet"]},
-      "Emily enrolled at school",
+      "Pupil enrolled at school",
       Protocol.UndefinedError
     ]