diff --git a/pyproject.toml b/pyproject.toml
index ae907c1..0c3af99 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -93,7 +93,6 @@ ignore = [
     "D417",
     "A002",
     "RUF012",
-    "ANN204",
 ]
 
 [tool.mypy]
diff --git a/raillabel/filter/_filter_classes/_filter_abc.py b/raillabel/filter/_filter_classes/_filter_abc.py
index 5de6b43..3346d37 100644
--- a/raillabel/filter/_filter_classes/_filter_abc.py
+++ b/raillabel/filter/_filter_classes/_filter_abc.py
@@ -31,7 +31,7 @@ def PARAMETERS(self) -> t.List[str]:
     def LEVELS(self) -> t.List[str]:
         raise NotImplementedError
 
-    def __init__(self, kwargs):
+    def __init__(self, kwargs) -> None:
         set_parameter = None
         for param in self.PARAMETERS:
             if param in kwargs and param is not None:
diff --git a/raillabel/format/_object_annotation.py b/raillabel/format/_object_annotation.py
index d69ed6f..9a01c59 100644
--- a/raillabel/format/_object_annotation.py
+++ b/raillabel/format/_object_annotation.py
@@ -114,7 +114,7 @@ def _attributes_fromdict(
 
     # === Special Methods ====================================================
 
-    def __post_init__(self):
+    def __post_init__(self) -> None:
         """Check for required arguments after __init__.
 
         Inheritance in dataclasses has the flaw, that when the parent class has fields with