diff --git a/02/game.py b/02/game.py
index 5a5ed7d04..03f272bfb 100644
--- a/02/game.py
+++ b/02/game.py
@@ -28,9 +28,10 @@ def input_word(draw):
 
 
 def _validation(word, draw):
+    unused_letters = list(draw) # copied because we are mutating the list
     for char in word.upper():
-        if char in draw:
-            draw.remove(char)
+        if char in unused_letters:
+            unused_letters.remove(char)
         else:
           raise ValueError("{} is not a valid word!".format(word))
     if not word.lower() in DICTIONARY:
diff --git a/02/test_game.py b/02/test_game.py
index 93888fa1e..b6fb49a61 100644
--- a/02/test_game.py
+++ b/02/test_game.py
@@ -40,13 +40,15 @@ def test_get_possible_dict_words(self):
         self.assertEqual(len(words), 137)
 
     def test_validation(self):
-        draw = list('garytev'.upper())
+        letters = list('garytev'.upper())
+        draw = list(letters)
         word = 'GARYTEV'
         self.assertRaises(ValueError, _validation, word, draw)
         word = 'F'
         self.assertRaises(ValueError, _validation, word, draw)
         word = 'GARETTA'
         self.assertRaises(ValueError, _validation, word, draw)
+        self.assertEqual(letters, draw)
 
 if __name__ == "__main__":
    unittest.main()