code: def __init__(self, on, at, neg):
      super().__init__(on, at, neg)
  
imports: from __future__ import annotations
  import abc
  import copy
  import math
  import numbers
  import typing
  from river import base, tree
label_desc: Use image node_id 1 to create a new NominalLiteral object from inherited base classes: Literal with example: obj = NominalLiteral(on, at, neg)