Use Optional[str] for values that could be None

#11
02b249e
https://mypy.readthedocs.io/en/latest/cheat_sheet_py3.html

inboard/app/utilities.py

@@ -1,7 +1,7 @@
 import base64
 import os
 from secrets import compare_digest
-from typing import Tuple, Union
+from typing import Optional, Tuple
 
 from fastapi import Depends, HTTPException, status
 from fastapi.security import HTTPBasic, HTTPBasicCredentials
@@ -17,7 +17,7 @@
 class BasicAuth(AuthenticationBackend):
     async def authenticate(
         self, request: HTTPConnection
-    ) -> Union[Tuple[AuthCredentials, SimpleUser], None]:
+    ) -> Optional[Tuple[AuthCredentials, SimpleUser]]:
         if "Authorization" not in request.headers:
             return None
 

inboard/gunicorn_conf.py

@@ -1,13 +1,13 @@
 import multiprocessing
 import os
-from typing import Union
+from typing import Optional
 
 from inboard.start import configure_logging
 
 
 def calculate_workers(
-    max_workers_str: Union[str, None],
-    web_concurrency_str: Union[str, None],
+    max_workers_str: Optional[str],
+    web_concurrency_str: Optional[str],
     workers_per_core_str: str,
     cores: int = multiprocessing.cpu_count(),
 ) -> int: