diff --git a/omegaconf/omegaconf.py b/omegaconf/omegaconf.py
index 4f204e86d..0edbbe986 100644
--- a/omegaconf/omegaconf.py
+++ b/omegaconf/omegaconf.py
@@ -797,16 +797,17 @@ def missing_keys(cfg: Union[Container, Any]) -> Set[str]:
         """
         if not isinstance(cfg, Container):
             try:
-                cfg = OmegaConf.create(cfg)  # type: ignore
+                cfg = OmegaConf.create(cfg)
             except ValidationError:
-                raise ValueError(f'Could not create a config out of {cfg}')
+                raise ValueError(f"Could not create a config out of {cfg}")
+        cfg: Container
         missings = set()
 
         def gather(_cfg: Container, prefix: str = "") -> None:
             if isinstance(_cfg, ListConfig):
-                itr = range(len(_cfg))
+                itr = range(len(_cfg))  # type: ignore
             else:
-                itr = _cfg
+                itr = _cfg  # type: ignore
 
             for key in itr:
                 if OmegaConf.is_missing(_cfg, key):
diff --git a/tests/test_omegaconf.py b/tests/test_omegaconf.py
index 1b2159e93..11effb244 100644
--- a/tests/test_omegaconf.py
+++ b/tests/test_omegaconf.py
@@ -640,6 +640,6 @@ def test_missing_keys(cfg: Any, expected: Any) -> None:
     "cfg",
     [float, int]
 )
-def test_missing_keys_invalid_input(cfg):
-    with raises(ValueError) as exc:
-        OmegaConf.missing_keys(cfg)  # type: ignore
+def test_missing_keys_invalid_input(cfg: Any) -> None:
+    with raises(ValueError):
+        OmegaConf.missing_keys(cfg)