title: Is there a way to create a python object that will be not sortable?
body: <p>Is there a possibility to create any python object that will be not sortable? So that will be an exception when trying to sort a list of that objects?
  I created a very simple class, didn't define any comparison methods, but still instances of this class are comparable and thus sortable. Maybe, my class inherits comparison methods from somewhere. But I don't want this behaviour.</p>