More type hints

radicale/app/options.py

@@ -19,11 +19,14 @@
 
 from http import client
 
-from radicale import httputils
+from radicale import httputils, types
+from radicale.app.base import ApplicationBase
 
 
-class ApplicationOptionsMixin:
-    def do_OPTIONS(self, environ, base_prefix, path, user):
+class ApplicationPartOptions(ApplicationBase):
+
+    def do_OPTIONS(self, environ: types.WSGIEnviron, base_prefix: str,
+                   path: str, user: str) -> types.WSGIResponse:
         """Manage OPTIONS request."""
         headers = {
             "Allow": ", ".join(