diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
index 43583fa..a116b42 100644
--- a/.github/workflows/test-package.yml
+++ b/.github/workflows/test-package.yml
@@ -66,7 +66,7 @@ jobs:
       env:
         DATABASE_URL: "sqlite:///testsuite"
       run: bash scripts/test.sh
-    - run: mypy --config-file mypy.ini ormar tests
+    - run: mypy ormar tests
     - name: Upload coverage
       uses: codecov/codecov-action@v1
     - name: Test & publish code coverage
diff --git a/ormar/queryset/prefetch_query.py b/ormar/queryset/prefetch_query.py
index cd15f45..873199c 100644
--- a/ormar/queryset/prefetch_query.py
+++ b/ormar/queryset/prefetch_query.py
@@ -30,11 +30,11 @@ def sort_models(models: List["Model"], orders_by: Dict) -> List["Model"]:
     ]
     sort_criteria = sort_criteria[::-1]
     for criteria in sort_criteria:
-        key, value = criteria
+        key_name, value = criteria
         if value == "desc":
-            models.sort(key=lambda x: getattr(x, key), reverse=True)
+            models.sort(key=lambda x: getattr(x, key_name), reverse=True)
         else:
-            models.sort(key=lambda x: getattr(x, key))
+            models.sort(key=lambda x: getattr(x, key_name))
     return models
 
 
diff --git a/ormar/queryset/utils.py b/ormar/queryset/utils.py
index 617d04e..f99c698 100644
--- a/ormar/queryset/utils.py
+++ b/ormar/queryset/utils.py
@@ -214,21 +214,22 @@ def extract_nested_models(  # noqa: CCR001
     follow = [rel for rel in model_type.extract_related_names() if rel in select_dict]
     for related in follow:
         child = getattr(model, related)
-        if child:
-            target_model = model_type.Meta.model_fields[related].to
-            if isinstance(child, list):
-                extracted.setdefault(target_model.get_name(), []).extend(child)
-                if select_dict[related] is not Ellipsis:
-                    for sub_child in child:
-                        extract_nested_models(
-                            sub_child, target_model, select_dict[related], extracted
-                        )
-            else:
-                extracted.setdefault(target_model.get_name(), []).append(child)
-                if select_dict[related] is not Ellipsis:
+        if not child:
+            continue
+        target_model = model_type.Meta.model_fields[related].to
+        if isinstance(child, list):
+            extracted.setdefault(target_model.get_name(), []).extend(child)
+            if select_dict[related] is not Ellipsis:
+                for sub_child in child:
                     extract_nested_models(
-                        child, target_model, select_dict[related], extracted
+                        sub_child, target_model, select_dict[related], extracted
                     )
+        else:
+            extracted.setdefault(target_model.get_name(), []).append(child)
+            if select_dict[related] is not Ellipsis:
+                extract_nested_models(
+                    child, target_model, select_dict[related], extracted
+                )
 
 
 def extract_models_to_dict_of_lists(
diff --git a/ormar/relations/querysetproxy.py b/ormar/relations/querysetproxy.py
index aaddacc..8170cf3 100644
--- a/ormar/relations/querysetproxy.py
+++ b/ormar/relations/querysetproxy.py
@@ -43,7 +43,7 @@ class QuerysetProxy(Generic[T]):
         type_: "RelationType",
         qryset: "QuerySet[T]" = None,
     ) -> None:
-        self.relation: Relation = relation
+        self.relation: "Relation" = relation
         self._queryset: Optional["QuerySet[T]"] = qryset
         self.type_: "RelationType" = type_
         self._owner: Union[CallableProxyType, "Model"] = self.relation.manager.owner