2 files changed, 6 insertions, 8 deletions
diff --git a/prolog/problems/family_relations/sister_2/common.py b/prolog/problems/family_relations/sister_2/common.py
index b3cbff0..6c48b00 100644
--- a/prolog/problems/family_relations/sister_2/common.py
+++ b/prolog/problems/family_relations/sister_2/common.py
@@ -24,7 +24,7 @@ sister(X, Y) :-
 hint_type = {
     'x_must_be_female': Hint('x_must_be_female'),
     'common_parent_needed': Hint('common_parent_needed'),
-    'Y_can_be_of_any_gender': Hint('Y_can_be_of_any_gender'),
+    'y_can_be_of_any_gender': Hint('Y_can_be_of_any_gender'),
     'x_y_must_be_different': Hint('x_y_must_be_different'),
 }
 
@@ -118,15 +118,13 @@ def hint(program, solved_problems):
         # this is an example of using the ordering of hints for easier trigger checks
         if prolog.engine.ask_one(engine_id,
             'sister(_, Y), male(Y)') == 'false':
-            return [{'id': 'Y_can_be_of_any_gender'}]
+            return [{'id': 'y_can_be_of_any_gender'}]
 
         # X and Y must be different
         # this is the last code-specific hint (when everything else doesn't trigger anymore)
-        ans = prolog.engine.ask_one(engine_id,
-            'setof(X, (member(X, [sally, nevia, vanessa]), sister(X, X)), L), length(L, N).')
-        # TODO this barfs if ans is 'false'
-        #if ans.get('N') == '3':
-        #    return [{'id': 'x_y_must_be_different'}]
+        if prolog.engine.ask_truth(engine_id,
+            'setof(X, (member(X, [sally, nevia, vanessa]), sister(X, X)), L), length(L, 3)'):
+            return [{'id': 'x_y_must_be_different'}]
 
         # last hints are connected with programming style
         # here, this means detecting such code:
diff --git a/prolog/problems/family_relations/sister_2/sl.py b/prolog/problems/family_relations/sister_2/sl.py
index aa66567..8c4c60f 100644
--- a/prolog/problems/family_relations/sister_2/sl.py
+++ b/prolog/problems/family_relations/sister_2/sl.py
@@ -37,7 +37,7 @@ hint = {
 <p>Sestra je navadno ženskega spola.</p>
 ''',
 
-    'Y_can_be_of_any_gender': '''\
+    'y_can_be_of_any_gender': '''\
 <p><code>Y</code> je pravzaprav lahko poljubnega spola.</p>
 ''',