Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdateManager.py", line 100, in <lambda>
    self.resize_to_standard_width())
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdateManager.py", line 141, in resize_to_standard_width
    GObject.signal_handler_block(ctx, self.signal_changed)
AttributeError: 'UpdateManager' object has no attribute 'signal_changed'