fix mypy

Author: raylu

pigwig/pigwig.py

@@ -10,7 +10,7 @@
 import urllib.parse
 import wsgiref.simple_server
 from inspect import isgenerator
-from typing import TYPE_CHECKING, Any, Callable, Iterable, Mapping, MutableMapping, TextIO
+from typing import TYPE_CHECKING, Any, Callable, Iterable, Mapping, MutableMapping, TextIO, cast
 
 from . import exceptions, multipart
 from .request_response import HTTPHeaders, Request, Response
@@ -114,7 +114,7 @@ def __init__(self, routes: RouteDefinition | Callable[[], RouteDefinition], temp
 
 	def __call__(self, environ: dict, start_response: Callable) -> Iterable[bytes]:
 		""" main WSGI entrypoint """
-		errors = environ.get('wsgi.errors', sys.stderr)
+		errors = cast(TextIO, environ.get('wsgi.errors', sys.stderr))
 		try:
 			if environ['REQUEST_METHOD'] == 'OPTIONS':
 				start_response('200 OK', copy.copy(Response.DEFAULT_HEADERS))

pyproject.toml

@@ -20,11 +20,12 @@ include = ['pigwig']
 exclude = ['pigwig.tests']
 [dependency-groups]
 dev = [
+    'mypy',
     'ruff',
 ]
 
 [tool.mypy]
-python_version = '3.8'
+python_version = '3.9'
 exclude = ['setup.py', 'docs/conf.py']
 disallow_untyped_defs = true
 implicit_reexport = false