code: def get_tuner_class(tuner):
      if isinstance(tuner, str) and tuner in TUNER_CLASSES:
          return TUNER_CLASSES.get(tuner)
      else:
          raise ValueError(
              'Expected the tuner argument to be one of "greedy", '
              '"random", "hyperband", or "bayesian", '
              "but got {tuner}".format(tuner=tuner)
          )
  
imports: from pathlib import Path
  from typing import List
  from typing import Optional
  from typing import Type
  from typing import Union
  import numpy
  import tensorflow
  from tensorflow import keras
  from tensorflow import nest
  from autokeras import blocks
  from autokeras import graph
  from autokeras import pipeline
  from autokeras import tuners
  from autokeras.engine import head
  from autokeras.engine import node
  from autokeras.engine import tuner
  from autokeras.nodes import Input
  from autokeras.utils import data_utils
  from autokeras.utils import utils
label_desc: Use image node_id 1 for calling a global function with example usage: get_tuner_class(tuner) and returns: TUNER_CLASSES