Apply suggestions of mypy

radicale/rights/__init__.py

@@ -57,6 +57,8 @@ def intersect(a: str, b: str) -> str:
 
 class BaseRights:
 
+    _user_groups: set[str] = set([])
+
     def __init__(self, configuration: "config.Configuration") -> None:
         """Initialize BaseRights.
 

radicale/rights/from_file.py

@@ -71,7 +71,7 @@ class Rights(rights.BaseRights):
                 collection_pattern = rights_config.get(section, "collection")
                 allowed_groups = rights_config.get(section, "groups", fallback="").split(",")
                 try:
-                    group_match = self._user_groups.intersection(allowed_groups) > 0
+                    group_match = len(self._user_groups.intersection(allowed_groups)) > 0
                 except Exception:
                     pass
                 # Use empty format() for harmonized handling of curly braces