Fixed lack of return statement

src/vpn_manager_globalprotect/backend.py

@@ -366,6 +366,11 @@ class GlobalProtectConnection(
             != "b"
         ):
             raise errors.InvalidOptions.invalid_type("use_default_browser", "b", sig)
+        if (
+            sig := options.get("firefox_browser_container", Variant("s", "")).signature
+            != "s"
+        ):
+            raise errors.InvalidOptions.invalid_type("use_default_browser", "s", sig)
 
     @classmethod
     def restore_options(cls, options: dict) -> dict[str, Variant]:
@@ -376,3 +381,5 @@ class GlobalProtectConnection(
         cls.put_value(result, "b", options, "verify_certificate")
         cls.put_value(result, "b", options, "allow_insecure_crypto")
         cls.put_value(result, "b", options, "use_default_browser")
+        cls.put_value(result, "s", options, "firefox_browser_container")
+        return result