diff --git a/ansibledoctor/config.py b/ansibledoctor/config.py
index 0876219d..9b00c090 100644
--- a/ansibledoctor/config.py
+++ b/ansibledoctor/config.py
@@ -2,6 +2,7 @@
 """Global settings definition."""
 
 import os
+from typing import ClassVar
 
 import anyconfig
 import environs
@@ -18,7 +19,7 @@
 default_envs_prefix = "ANSIBLE_DOCTOR_"
 
 
-class Config():
+class Config:
     """
     Create an object with all necessary settings.
 
@@ -28,7 +29,7 @@ class Config():
     - provides cli parameters
     """
 
-    SETTINGS = {
+    SETTINGS: ClassVar[dict[dict]] = {
         "config_file": {
             "default": default_config_file,
             "env": "CONFIG_FILE",
@@ -125,7 +126,7 @@ class Config():
         },
     }
 
-    ANNOTATIONS = {
+    ANNOTATIONS: ClassVar[dict[dict]] = {
         "meta": {
             "name": "meta",
             "automatic": True,
diff --git a/ansibledoctor/file_registry.py b/ansibledoctor/file_registry.py
index adbe4863..43d6e1fb 100644
--- a/ansibledoctor/file_registry.py
+++ b/ansibledoctor/file_registry.py
@@ -14,10 +14,6 @@
 class Registry:
     """Register all yaml files."""
 
-    _doc = {}
-    log = None
-    config = None
-
     def __init__(self):
         self._doc = []
         self.config = SingleConfig()
diff --git a/ansibledoctor/utils.py b/ansibledoctor/utils.py
index e8266e03..912c5b87 100644
--- a/ansibledoctor/utils.py
+++ b/ansibledoctor/utils.py
@@ -6,6 +6,7 @@
 import sys
 from collections.abc import Iterable
 from distutils.util import strtobool
+from typing import ClassVar
 
 import colorama
 from pythonjsonlogger import jsonlogger
@@ -77,7 +78,7 @@ def _split_string(string, delimiter, escape, maxsplit=None):
 class Singleton(type):
     """Meta singleton class."""
 
-    _instances = {}
+    _instances: ClassVar[dict] = {}
 
     def __call__(cls, *args, **kwargs):
         if cls not in cls._instances: