diff --git a/popmon/visualization/alert_section_generator.py b/popmon/visualization/alert_section_generator.py
index b0b0a122..c28c0811 100644
--- a/popmon/visualization/alert_section_generator.py
+++ b/popmon/visualization/alert_section_generator.py
@@ -42,9 +42,9 @@ def __init__(
         self,
         read_key,
         store_key,
+        settings: Report,
         features=None,
         ignore_features=None,
-        settings: Report = None,
         static_bounds=None,
         dynamic_bounds=None,
         prefix="traffic_light_",
diff --git a/popmon/visualization/histogram_section.py b/popmon/visualization/histogram_section.py
index 11ddc722..a54b4e22 100644
--- a/popmon/visualization/histogram_section.py
+++ b/popmon/visualization/histogram_section.py
@@ -46,8 +46,8 @@ def __init__(
         self,
         read_key,
         store_key,
+        settings: HistogramSectionModel,
         features=None,
-        settings: HistogramSectionModel = None,
         ignore_features=None,
         hist_names=None,
         hist_name_starts_with="histogram",
diff --git a/popmon/visualization/traffic_light_section_generator.py b/popmon/visualization/traffic_light_section_generator.py
index 21408895..e737f00b 100644
--- a/popmon/visualization/traffic_light_section_generator.py
+++ b/popmon/visualization/traffic_light_section_generator.py
@@ -47,9 +47,9 @@ def __init__(
         self,
         read_key,
         store_key,
+        settings: Report,
         features=None,
         ignore_features=None,
-        settings: Report = None,
         static_bounds=None,
         dynamic_bounds=None,
         prefix="traffic_light_",