diff --git a/src/treequest/algos/ab_mcts_m/algo.py b/src/treequest/algos/ab_mcts_m/algo.py
index d54d2dd..9bb8520 100644
--- a/src/treequest/algos/ab_mcts_m/algo.py
+++ b/src/treequest/algos/ab_mcts_m/algo.py
@@ -19,7 +19,7 @@
 
 StateT = TypeVar("StateT")
 
-_WORKER_ALGO = None
+_WORKER_ALGO: Optional["ABMCTSM"] = None
 
 
 def _worker_init_abmctsm(config: dict, per_worker_cpu_devices: int):
diff --git a/src/treequest/vis/renderers/html.py b/src/treequest/vis/renderers/html.py
index 6489978..ea6a71d 100644
--- a/src/treequest/vis/renderers/html.py
+++ b/src/treequest/vis/renderers/html.py
@@ -4,14 +4,14 @@
 from typing import Callable, Dict, List, Optional, Union
 
 from treequest.vis.errors import DependencyNotFoundError, RenderError
-from treequest.vis.snapshot import VisualizationSnapshot
-from treequest.vis.renderers.json_yaml import snapshot_to_dict
 from treequest.vis.renderers.color_utils import (
     ROOT_COLOR,
     ColorMap,
     apply_status_color,
     resolve_colormap,
 )
+from treequest.vis.renderers.json_yaml import snapshot_to_dict
+from treequest.vis.snapshot import VisualizationSnapshot
 
 
 def _get_d3_js() -> str: