diff --git a/galactory/models.py b/galactory/models.py
index 957bfd5..923d3a2 100644
--- a/galactory/models.py
+++ b/galactory/models.py
@@ -162,7 +162,7 @@ def __setitem__(self, key: t.Union[str, VersionInfo], item: CollectionData) -> N
     def __delitem__(self, key: t.Union[str, VersionInfo]) -> None:
         return super().__delitem__(self._get_key(key))
 
-    def __contains__(self, key: object) -> bool:
+    def __contains__(self, key: t.Union[str, VersionInfo]) -> bool:
         return super().__contains__(self._get_key(key, raises=False))
 
     # re-define for the type hints
diff --git a/tests/unit/models/test_collectiongroup.py b/tests/unit/models/test_collectiongroup.py
index 17bc43b..97964fb 100644
--- a/tests/unit/models/test_collectiongroup.py
+++ b/tests/unit/models/test_collectiongroup.py
@@ -84,7 +84,16 @@ def test_collectiongroup_add(mocker: MockFixture, namespace, name, collection_da
 
 
     colgroup.add(collection_data)
+    spy.assert_called_once_with(colgroup, collection_data.semver, collection_data)
     assert len(colgroup) == 1
     assert colgroup.latest is collection_data
 
-    spy.assert_called_once_with(colgroup, collection_data.semver, collection_data)
+
+def test_collectiongroup_from_collection(mocker: MockFixture, collection_data: CollectionData):
+    spy = mocker.spy(CollectionGroup, '__init__')
+
+    colgroup = CollectionGroup.from_collection(collection_data)
+
+    spy.assert_called_once_with(mocker.ANY, namespace=collection_data.namespace, name=collection_data.name)
+    assert len(colgroup) == 1
+    assert colgroup.latest is collection_data