diff --git a/dagmc/dagnav.py b/dagmc/dagnav.py
index 27abe26..52312b4 100644
--- a/dagmc/dagnav.py
+++ b/dagmc/dagnav.py
@@ -55,7 +55,7 @@ def groups(self) -> Dict[str, Group]:
         return group_mapping
 
     def __repr__(self):
-        return f'{type(self).__name__} {self.id}, {self.num_triangles()} triangles'
+        return f'{type(self).__name__} {self.id}, {self.num_triangles} triangles'
 
     @cached_property
     def id_tag(self):
@@ -188,7 +188,7 @@ def __hash__(self):
         return hash((self.handle, id(self.model)))
 
     def __repr__(self):
-        return f'{type(self).__name__} {self.id}, {self.num_triangles()} triangles'
+        return f'{type(self).__name__} {self.id}, {self.num_triangles} triangles'
 
     def _tag_get_data(self, tag: tag.Tag):
         return self.model.mb.tag_get_data(tag, self.handle, flat=True)[0]
diff --git a/test/test_basic.py b/test/test_basic.py
index bbaf177..54a4f22 100644
--- a/test/test_basic.py
+++ b/test/test_basic.py
@@ -99,7 +99,7 @@ def test_group_merge(request):
     new_group = dagmc.Group.create(model, 'mat:fuel')
 
     # add one of other volumes to the new set
-    for vol in model.volumes.values():
+    for vol in model.volumes:
         new_group.add_set(vol)
 
     assert orig_group != new_group