diff --git a/stubs/reportlab/@tests/stubtest_allowlist.txt b/stubs/reportlab/@tests/stubtest_allowlist.txt
index da619dcf1c38..4e5160000e35 100644
--- a/stubs/reportlab/@tests/stubtest_allowlist.txt
+++ b/stubs/reportlab/@tests/stubtest_allowlist.txt
@@ -104,7 +104,8 @@ reportlab.graphics.barcode.eanbc.isEanString
 
 # Error: is not present at runtime
 # ================================
-# PropertySet can have arbitrary attributes, so we add a __getattr_
+# These can have arbitrary attributes, so we add a __getattr__
+reportlab.lib.abag.ABag.__getattr__
 reportlab.lib.styles.PropertySet.__getattr__
 
 # Only exists on renderPM backend
diff --git a/stubs/reportlab/reportlab/lib/abag.pyi b/stubs/reportlab/reportlab/lib/abag.pyi
index b9b4b29db9e0..4c7d4d6851a0 100644
--- a/stubs/reportlab/reportlab/lib/abag.pyi
+++ b/stubs/reportlab/reportlab/lib/abag.pyi
@@ -3,7 +3,9 @@ from typing_extensions import Self
 
 __version__: Final[str]
 
-# NOTE: just holds an arbitrary collection of attributes, so we subclass Any
-class ABag(Any):
+class ABag:
     def __init__(self, **attr: Any) -> None: ...
     def clone(self, **attr: Any) -> Self: ...
+    # ABag can have arbitrary attributes
+    def __getattr__(self, name: str) -> Any: ...
+    def __setattr__(self, name: str, value: Any) -> None: ...