diff --git a/apps/marks/models.py b/apps/marks/models.py
index 19494cc43..b5d83797d 100644
--- a/apps/marks/models.py
+++ b/apps/marks/models.py
@@ -197,7 +197,7 @@ def _get_with_duration_and_vacation(added_date=timezone.now()):
     if added_date < mark_change_date:
         duration = 30
 
-    if type(added_date) == datetime:
+    if isinstance(added_date, datetime):
         added_date = added_date.date()
 
     # Add the duration
diff --git a/apps/sso/serializers.py b/apps/sso/serializers.py
index 731cf82b9..4b6f64e26 100644
--- a/apps/sso/serializers.py
+++ b/apps/sso/serializers.py
@@ -23,9 +23,9 @@ def to_representation(self, value):
         return value.split()
 
     def to_internal_value(self, data):
-        if type(data) == list:
+        if isinstance(data, list):
             return " ".join(data)
-        elif type(data) == str:
+        elif isinstance(data, str):
             return data.replace("\r\n", " ")
         else:
             raise ValidationError("Incorrect format")