diff --git a/aleph_message/models/__init__.py b/aleph_message/models/__init__.py
index 4f15e42..e84adbe 100644
--- a/aleph_message/models/__init__.py
+++ b/aleph_message/models/__init__.py
@@ -11,9 +11,9 @@
 
 from .abstract import BaseContent
 from .base import Chain, HashType, MessageType
+from .execution.base import MachineType, Payment, PaymentType  # noqa
 from .execution.instance import InstanceContent
 from .execution.program import ProgramContent
-from .execution.base import PaymentType, MachineType, Payment  # noqa
 from .item_hash import ItemHash, ItemType
 
 
diff --git a/aleph_message/models/execution/abstract.py b/aleph_message/models/execution/abstract.py
index 833ba7c..c6271b5 100644
--- a/aleph_message/models/execution/abstract.py
+++ b/aleph_message/models/execution/abstract.py
@@ -5,14 +5,10 @@
 
 from pydantic import Field
 
-from .environment import (
-    FunctionEnvironment,
-    HostRequirements,
-    MachineResources,
-)
+from ..abstract import BaseContent, HashableModel
 from .base import Payment
+from .environment import FunctionEnvironment, HostRequirements, MachineResources
 from .volume import MachineVolume
-from ..abstract import BaseContent, HashableModel
 
 
 class BaseExecutableContent(HashableModel, BaseContent, ABC):
diff --git a/aleph_message/models/execution/program.py b/aleph_message/models/execution/program.py
index 344d4d6..8afb6d9 100644
--- a/aleph_message/models/execution/program.py
+++ b/aleph_message/models/execution/program.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Literal, Optional, List
+from typing import List, Literal, Optional
 
 from pydantic import Field