diff --git a/apps/assets/api/asset/common.py b/apps/assets/api/asset/common.py
index 007d7fbd0..fb949f7ef 100644
--- a/apps/assets/api/asset/common.py
+++ b/apps/assets/api/asset/common.py
@@ -37,17 +37,17 @@ class AssetViewSet(SuggestionMixin, FilterAssetByNodeMixin, OrgBulkModelViewSet)
     search_fields = ("hostname", "ip")
     ordering_fields = ("hostname", "ip", "port")
     ordering = ('hostname', )
-    serializer_classes = {
-        'default': serializers.AssetSerializer,
-        'suggestion': serializers.MiniAssetSerializer,
-        'platform': serializers.PlatformSerializer,
-        'gateways': serializers.GatewayWithAuthSerializer
-    }
-    rbac_perms = {
-        'match': 'assets.match_asset',
-        'platform': 'assets.view_platform',
-        'gateways': 'assets.view_gateway'
-    }
+    serializer_classes = (
+        ('default', serializers.AssetSerializer),
+        ('suggestion', serializers.MiniAssetSerializer),
+        ('platform', serializers.PlatformSerializer),
+        ('gateways', serializers.GatewayWithAuthSerializer)
+    )
+    rbac_perms = (
+        ('match', 'assets.match_asset'),
+        ('platform', 'assets.view_platform'),
+        ('gateways', 'assets.view_gateway')
+    )
     extra_filter_backends = [
         FilterAssetByNodeFilterBackend,
         LabelFilterBackend,
diff --git a/apps/assets/serializers/asset/category.py b/apps/assets/serializers/asset/category.py
index 6d9ab1bf0..0b01bb0a2 100644
--- a/apps/assets/serializers/asset/category.py
+++ b/apps/assets/serializers/asset/category.py
@@ -52,17 +52,3 @@ class DatabaseSerializer(AssetSerializer):
             **AssetSerializer.Meta.extra_kwargs,
             'db_name': {'required': True}
         }
-
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        if not self.instance:
-            self.set_port_default()
-
-    def set_port_default(self):
-        port = self.fields['port']
-        type_port_mapper = {
-            'mysql': 3306,
-            'postgresql': 5432,
-            'oracle': 22
-        }
-        port.default = ''
diff --git a/apps/common/mixins/api/serializer.py b/apps/common/mixins/api/serializer.py
index a416fa990..84cad19ff 100644
--- a/apps/common/mixins/api/serializer.py
+++ b/apps/common/mixins/api/serializer.py
@@ -16,28 +16,29 @@ class SerializerMixin:
     single_actions = ['put', 'retrieve', 'patch']
 
     def get_serializer_classes(self):
-        return getattr(self, 'serializer_classes', None)
+        classes = getattr(self, 'serializer_classes', None) or {}
+        return dict(classes)
 
     def get_serializer_class_by_view_action(self):
         serializer_classes = self.get_serializer_classes()
         if serializer_classes is None:
             return None
-        if not isinstance(self.serializer_classes, dict):
+        if not isinstance(serializer_classes, dict):
             return None
-
+        serializer_classes = dict(serializer_classes)
         view_action = self.request.query_params.get('action') or self.action or 'list'
-        serializer_class = self.serializer_classes.get(view_action)
+        serializer_class = serializer_classes.get(view_action)
 
         if serializer_class is None:
             view_method = self.request.method.lower()
-            serializer_class = self.serializer_classes.get(view_method)
+            serializer_class = serializer_classes.get(view_method)
 
         if serializer_class is None and view_action in self.single_actions:
-            serializer_class = self.serializer_classes.get('single')
+            serializer_class = serializer_classes.get('single')
         if serializer_class is None:
-            serializer_class = self.serializer_classes.get('display')
+            serializer_class = serializer_classes.get('display')
         if serializer_class is None:
-            serializer_class = self.serializer_classes.get('default')
+            serializer_class = serializer_classes.get('default')
         return serializer_class
 
     def get_serializer_class(self):
diff --git a/apps/rbac/permissions.py b/apps/rbac/permissions.py
index 3538246b7..286e5b935 100644
--- a/apps/rbac/permissions.py
+++ b/apps/rbac/permissions.py
@@ -93,7 +93,8 @@ class RBACPermission(permissions.DjangoModelPermissions):
         try:
             queryset = self._queryset(view)
             model_cls = queryset.model
-        except:
+        except Exception as e:
+            raise e
             model_cls = None
         return model_cls