Fix all typing issues

tagging/docker_runner.py

@@ -1,6 +1,7 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 from typing import Optional
+from types import TracebackType
 import docker
 from docker.models.containers import Container
 import logging
@@ -13,7 +14,7 @@ class DockerRunner:
     def __init__(
         self,
         image_name: str,
-        docker_client=docker.from_env(),
+        docker_client: docker.DockerClient = docker.from_env(),
         command: str = "sleep infinity",
     ):
         self.container: Optional[Container] = None
@@ -31,7 +32,13 @@ class DockerRunner:
         LOGGER.info(f"Container {self.container.name} created")
         return self.container
 
-    def __exit__(self, exc_type, exc_value, traceback) -> None:
+    def __exit__(
+        self,
+        exc_type: Optional[type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
+        assert self.container is not None
         LOGGER.info(f"Removing container {self.container.name} ...")
         if self.container:
             self.container.remove(force=True)
@@ -44,6 +51,7 @@ class DockerRunner:
         LOGGER.info(f"Running cmd: '{cmd}' on container: {container}")
         out = container.exec_run(cmd)
         result = out.output.decode("utf-8").rstrip()
+        assert isinstance(result, str)
         if print_result:
             LOGGER.info(f"Command result: {result}")
         assert out.exit_code == 0, f"Command: {cmd} failed"