diff --git a/python/src/trezorlib/cli/__init__.py b/python/src/trezorlib/cli/__init__.py
index b2fc89255c..da2a126eba 100644
--- a/python/src/trezorlib/cli/__init__.py
+++ b/python/src/trezorlib/cli/__init__.py
@@ -146,7 +146,7 @@ class TrezorConnection:
         client = self.get_client()
         if must_resume and self.session_id is None:
             click.echo("Failed to resume session - no session id provided")
-            return None
+            raise RuntimeError("Failed to resume session - no session id provided")
 
         # Try resume session from id
         if self.session_id is not None:
@@ -162,7 +162,7 @@ class TrezorConnection:
             if must_resume:
                 if session.id != self.session_id or session.id is None:
                     click.echo("Failed to resume session")
-                    return None
+                    RuntimeError("Failed to resume session - no session id provided")
             return session
 
         features = client.protocol.get_features()
diff --git a/python/src/trezorlib/transport/thp/protocol_v1.py b/python/src/trezorlib/transport/thp/protocol_v1.py
index ca5b3c8b30..baea7e7401 100644
--- a/python/src/trezorlib/transport/thp/protocol_v1.py
+++ b/python/src/trezorlib/transport/thp/protocol_v1.py
@@ -1,4 +1,5 @@
 from __future__ import annotations
+
 import logging
 import struct
 import typing as t