<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def avoid(self) -> Set[int]: """ Returns a set of word IDs that should be avoided. This includes the set of final states from the root node, which are single tokens that must never be generated. :return: A set of integers representing words that must not be generated next by this hypothesis. """

        return self.root.final() | self.state.final()