diff --git a/smarttree/_check.py b/smarttree/_check.py
index d9c1ad1..0469d50 100644
--- a/smarttree/_check.py
+++ b/smarttree/_check.py
@@ -316,7 +316,7 @@ def _check__rank_na_mode(rank_na_mode):
     if rank_na_mode not in ("include_all", "include_best"):
         raise ValueError(
             "`rank_na_mode` must be Literal['include_all', 'include_best']."
-            f" The current value of `na_mode` is {rank_na_mode!r}."
+            f" The current value of `rank_na_mode` is {rank_na_mode!r}."
         )
 
 
diff --git a/tests/decision_tree/base/test__check_params.py b/tests/decision_tree/base/test__check_params.py
index 2bcd540..822e58f 100644
--- a/tests/decision_tree/base/test__check_params.py
+++ b/tests/decision_tree/base/test__check_params.py
@@ -7,6 +7,7 @@
 from smarttree._types import (
     CatNaModeType,
     ClassificationCriterionType,
+    CommonNaModeType,
     NaModeType,
     NumNaModeType,
 )
@@ -559,6 +560,31 @@ def test__check_params__hierarchy(hierarchy, expected_context):
         SmartDecisionTreeClassifier(hierarchy=hierarchy)
 
 
+@pytest.mark.parametrize(
+    ("na_mode", "expected_context"),
+    [
+        ("include_all", does_not_raise()),
+        ("include_best", does_not_raise()),
+        (
+            "smth",
+            pytest.raises(
+                ValueError,
+                match=re.escape(
+                    "`na_mode` must be Literal['include_all', 'include_best']."
+                    " The current value of `na_mode` is 'smth'."
+                ),
+            ),
+        ),
+    ],
+    ids=["include_all", "include_best", "invalid"],
+)
+def test__check_params__na_mode(na_mode, expected_context):
+    with expected_context:
+        na_mode: CommonNaModeType
+        SmartDecisionTreeClassifier(na_mode=na_mode)
+
+
+
 @pytest.mark.parametrize(
     ("num_na_mode", "expected_context"),
     [
@@ -632,6 +658,30 @@ def test__check_param__cat_na_filler(cat_na_filler, expected_context):
         SmartDecisionTreeClassifier(cat_na_filler=cat_na_filler)
 
 
+@pytest.mark.parametrize(
+    ("rank_na_mode", "expected_context"),
+    [
+        ("include_all", does_not_raise()),
+        ("include_best", does_not_raise()),
+        (
+            "smth",
+            pytest.raises(
+                ValueError,
+                match=re.escape(
+                    "`rank_na_mode` must be Literal['include_all', 'include_best']."
+                    " The current value of `rank_na_mode` is 'smth'."
+                ),
+            ),
+        ),
+    ],
+    ids=["include_all", "include_best", "invalid"],
+)
+def test__check_params__rank_na_mode(rank_na_mode, expected_context):
+    with expected_context:
+        rank_na_mode: CommonNaModeType
+        SmartDecisionTreeClassifier(rank_na_mode=rank_na_mode)
+
+
 @pytest.mark.parametrize(
     ("min_samples_split", "min_samples_leaf", "expected_context"),
     [
@@ -700,5 +750,5 @@ def test__check_params__min_samples_split__min_samples_leaf(
 )
 def test__check_params__feature_na_mode(feature_na_mode, expected_context):
     with expected_context:
-        feature_na_mode: dict[str, NaModeType | None]
+        feature_na_mode: dict[str, NaModeType]
         SmartDecisionTreeClassifier(feature_na_mode=feature_na_mode)