"Resolve unsoundness caught by pytype --strict-none-binding.

See go/pytype-releases#strict-none-binding and go/pytype-smarter-optional. In
short, pytype was previously more permissive when variables were initialized to
None but may have been re-assigned later. This change improves pytype's ability
to catch unsoundness in the affected files.

PiperOrigin-RevId: 567950912

android_env/components/simulators/emulator/emulator_simulator.py

@@ -272,6 +272,7 @@ def load_state(
       * If an error occurred during the snapshot loading process, the status
         will be `ERROR` and the `error_message` field will be filled.
     """
+    assert self._snapshot_stub is not None
     snapshot_name = request.args.get('snapshot_name', _DEFAULT_SNAPSHOT_NAME)
     snapshot_list = self._snapshot_stub.ListSnapshots(
         snapshot_service_pb2.SnapshotFilter(
@@ -317,6 +318,8 @@ def save_state(
       * If an error occurred during the snapshot saving process, the status
         will be `ERROR` and the `error_message` field will be filled.
     """
+    assert self._snapshot_stub is not None
+
     snapshot_name = request.args.get('snapshot_name', _DEFAULT_SNAPSHOT_NAME)
     snapshot_result = self._snapshot_stub.SaveSnapshot(
         snapshot_service_pb2.SnapshotPackage(snapshot_id=snapshot_name)