diff --git a/20170613-mock/code/ggee/guessing/game.py b/20170613-mock/code/ggee/guessing/game.py
index ddc610b..60d6e10 100755
--- a/20170613-mock/code/ggee/guessing/game.py
+++ b/20170613-mock/code/ggee/guessing/game.py
@@ -19,6 +19,35 @@
 # TODO: implement a high-score
 # see https://github.com/chenl/talks/issues/4
 
+class PromptGGEE(object):
+    """This class was made to work around a problem,
+     where a string is translated before formatting.
+
+     E.g. a part like `{level}` might translate too,
+     thus breaking the formatting.
+
+     This class allows to replace `{level}` with `{0:0}`:
+     >>> prompt = PromptGGEE(3, 7, 5)
+     >>> 'using level {0:0}'.format(prompt)
+
+     Using a fixed mapping between indices (0) and attrs (level),
+     we prevent the translation of any attr.
+    """
+
+    attr_by_index = {'0': 'level', '1': 'max_num', '2': 'num'}
+
+    def __init__(self, level, max_num, num):
+        self.level = str(level)
+        self.max_num = str(max_num)
+        self.num = str(num)
+
+    def __getitem__(self, item):
+        attr = self.attr_by_index[item]
+        return getattr(self, attr)
+
+    def __format__(self, format_spec):
+        return self[format_spec]
+
 def game():
     # type: () -> None
     intro()
@@ -47,14 +76,14 @@ def think_of_a_number(level):
 
 def play(level):
     # type: (int) -> None
-    print(T("Level {level}: 0 to {max_num}").format(
-        level=level, max_num=max_number(level)))
     num = think_of_a_number(level)
+    prompt = PromptGGEE(level=level, max_num=max_number(level), num=num)
+    print(T("Level {0:0}: 0 to {0:1}").format(prompt))
     while True:
         print(T("Can you guess what number I am thinking about?"))
         guess = your_guess()
         if guess is None:
-            print(T("Just wanted you to know that I was thinking about {}").format(num))
+            print(T("Just wanted you to know that I was thinking about {0:2}").format(prompt))
             break
         if guess < num:
             print(T("No, my number is bigger than that"))
diff --git a/20170613-mock/code/ggee/tests/test_game.py b/20170613-mock/code/ggee/tests/test_game.py
index 4eafeaf..15c0b09 100644
--- a/20170613-mock/code/ggee/tests/test_game.py
+++ b/20170613-mock/code/ggee/tests/test_game.py
@@ -3,10 +3,9 @@
 import pytest
 
 try:
-    from io import StringIO
-except ImportError:
-    #from io import BytesIO as StringIO
     from StringIO import StringIO
+except ImportError:
+    from io import StringIO
 
 try:
     from unittest import mock
@@ -88,9 +87,16 @@ def test_your_guess_quit(mock_stdout, mock_readline, mock_lang):
     )
 
 
+def test_PromptGGEE():
+    prompt = game.PromptGGEE(level=3, max_num=7, num=5)
+    assert '{0:0} {0:1} {0:2}'.format(prompt) == '3 7 5'
+    assert '{a} {b:1} {c}'.format(a='a', b=prompt, c='c') == 'a 7 c'
+    assert 'simple'.format(prompt) == 'simple'
+
+
 @pytest.mark.parametrize('guesses,expected_messages', [
     ([4, 6, 5], [  # full scenario
-        "Level 3: 0 to 7",
+        "Level {0:0}: 0 to {0:1}",
         "Can you guess what number I am thinking about?",
         "No, my number is bigger than that",
         "Can you guess what number I am thinking about?",
@@ -99,12 +105,12 @@ def test_your_guess_quit(mock_stdout, mock_readline, mock_lang):
         "Yes, this is the number I was thinking about! How did you know that?",
     ]),
     ([None], [     # empty scenario
-        "Level 3: 0 to 7",
+        "Level {0:0}: 0 to {0:1}",
         "Can you guess what number I am thinking about?",
-        "Just wanted you to know that I was thinking about 5",
+        "Just wanted you to know that I was thinking about {0:2}",
     ]),
     ([5], [        # lucky scenario
-        "Level 3: 0 to 7",
+        "Level {0:0}: 0 to {0:1}",
         "Can you guess what number I am thinking about?",
         "Yes, this is the number I was thinking about! How did you know that?",
     ]),
@@ -120,5 +126,9 @@ def test_play(mock_stdout, mock_T, guesses, expected_messages):
             mock.patch('guessing.game.your_guess', side_effect=guesses):
         game.play(level)
 
-    mock_T.call_args_list = map(mock.call, expected_messages)
-    assert mock_stdout.getvalue() == '\n'.join(expected_messages) + '\n'
+    assert mock_T.call_args_list == map(mock.call, expected_messages)
+
+    prompt = game.PromptGGEE(level=level, max_num=7, num=num)
+    printed_messages = [msg.format(prompt) + '\n'
+                        for msg in expected_messages]
+    assert mock_stdout.getvalue() == ''.join(printed_messages)