Subclasses should not set attributes that are set in the superclass. Doing so may violate invariants in the superclass.

If you did not intend to override the attribute value set in the superclass, then rename the subclass attribute. If you do want to be able to set a new value for the attribute of the superclass, then convert the superclass attribute to a property. Otherwise the value should be passed as a parameter to the superclass __init__ method.