mypy compliance

Author: moderouin

axelrod/strategies/attention.py

@@ -352,7 +352,7 @@ def __init__(
         self,
     ) -> None:
         super().__init__()
-        self.model = None
+        self.model: Optional[PlayerModel] = None
 
     def load_model(self) -> None:
         """Load the model weights."""
@@ -366,6 +366,8 @@ def strategy(self, opponent: Player) -> Action:
         """Actual strategy definition that determines player's action."""
         # Load the model if not already loaded
         self.load_model()
+        assert self.model is not None, "Model must be loaded before playing."
+
         # Compute features
         features = compute_features(self, opponent).unsqueeze(0).to(DEVICES)