code: def __call__(self, x):
      if self.on in x:
          if not self.neg:
              return x[self.on] == self.at
          else:
              return x[self.on] != self.at
  
      return False
  
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 2 for calling the NominalLiteral obj's underlying member method code with example usage: obj.__call__(x) and returns: False, unknown, unknown