Make entry point collections (more) immutable.

Author: jaraco

importlib_metadata/__init__.py

@@ -157,9 +157,11 @@ def __reduce__(self):
 
 class EntryPoints(tuple):
     """
-    A collection of EntryPoint objects, retrievable by name.
+    An immutable collection of EntryPoint objects, retrievable by name.
     """
 
+    __slots__ = ()
+
     def __getitem__(self, name) -> EntryPoint:
         try:
             return next(ep for ep in self if ep.name == name)
@@ -173,9 +175,11 @@ def names(self):
 
 class GroupedEntryPoints(tuple):
     """
-    A collection of EntryPoint objects, retrievable by group.
+    An immutable collection of EntryPoint objects, retrievable by group.
     """
 
+    __slots__ = ()
+
     def __getitem__(self, group) -> EntryPoints:
         return EntryPoints(ep for ep in self if ep.group == group)