diff --git a/ormar/fields/base.py b/ormar/fields/base.py
index 9325535..3310d25 100644
--- a/ormar/fields/base.py
+++ b/ormar/fields/base.py
@@ -195,7 +195,7 @@ class BaseField(FieldInfo):
                 if self.ormar_default is not None
                 else (self.server_default if use_server else None)
             )
-            if callable(default):
+            if callable(default):  # pragma: no cover
                 default = default()
             return default
 
diff --git a/ormar/models/mixins/save_mixin.py b/ormar/models/mixins/save_mixin.py
index 56a2d9c..f96c3b9 100644
--- a/ormar/models/mixins/save_mixin.py
+++ b/ormar/models/mixins/save_mixin.py
@@ -113,7 +113,7 @@ class SavePrepareMixin(RelationMixin, AliasMixin):
             if field_value is not None:
                 target_field = cls.Meta.model_fields[field]
                 target_pkname = target_field.to.Meta.pkname
-                if isinstance(field_value, ormar.Model):
+                if isinstance(field_value, ormar.Model):  # pragma: no cover
                     pk_value = getattr(field_value, target_pkname)
                     if not pk_value:
                         raise ModelPersistenceError(
diff --git a/ormar/queryset/queryset.py b/ormar/queryset/queryset.py
index 1c8b8d8..ef4b434 100644
--- a/ormar/queryset/queryset.py
+++ b/ormar/queryset/queryset.py
@@ -602,7 +602,7 @@ class QuerySet(Generic[T]):
         ]
         if _as_dict:
             return result
-        if _flatten and not self._excludable.include_entry_count() == 1:
+        if _flatten and self._excludable.include_entry_count() != 1:
             raise QueryDefinitionError(
                 "You cannot flatten values_list if more than one field is selected!"
             )
diff --git a/tests/test_model_definition/test_create_uses_init_for_consistency.py b/tests/test_model_definition/test_create_uses_init_for_consistency.py
index c95d885..c6fedba 100644
--- a/tests/test_model_definition/test_create_uses_init_for_consistency.py
+++ b/tests/test_model_definition/test_create_uses_init_for_consistency.py
@@ -43,8 +43,8 @@ class Mol(ormar.Model):
 
     @classmethod
     def uuid(cls, smiles):
-        id = uuid.uuid5(cls._UUID_NAMESPACE, smiles)
-        return id, smiles
+        id_ = uuid.uuid5(cls._UUID_NAMESPACE, smiles)
+        return id_, smiles
 
 
 @pytest.fixture(autouse=True, scope="module")