usb1: Replace lambda in finalizer argument with partial

While it seems the lambda instance does not keep a reference to
setPollFDNotifiers's stack cell (which would cause the finalizer to keep a
reference to the object it is monitoring, preventing proper finalization)
in cPython 3.11, I am not confident this would be also the case in other
implementations and versions. I do not expect functools.partial instances
to keep any reference to their call stack, so they seem safer in such
reference-sensitive context.

Author: vpelletier

usb1/__init__.py

@@ -2430,7 +2430,10 @@ def setPollFDNotifiers(
                     self,
                     self.__finalizePollFDNotifiers, # Note: staticmethod
                     context_p=self.__context_p,
-                    unregisterFinalizer=lambda: finalizer_dict.pop(finalizer_handle),
+                    unregisterFinalizer=functools.partial(
+                        finalizer_dict.pop,
+                        finalizer_handle,
+                    ),
                     libusb_set_pollfd_notifiers=libusb1.libusb_set_pollfd_notifiers,
                 )
                 self.__registerFinalizer(finalizer_handle, finalizer)