code: def test_invalid_return_type_in_get_iterator(self):
      x = np.random.random((100, 16))
      y = np.random.random((100, 4))
      epoch_iter = epoch_iterator.EpochIterator(x=x, y=y)
  
      with self.assertRaisesRegex(
          ValueError,
          "Argument `return_type` must be one of `{'np', 'tf', 'auto'}`",
      ):
          _ = epoch_iter._get_iterator("unsupported")
  
imports: import numpy
  import pytest
  import tensorflow
  from keras import backend
  from keras import testing
  from keras.trainers import data_adapters
  from keras.trainers import epoch_iterator
label_desc: Use image node_id 12 for calling the TestEpochIterator obj's underlying member method code with example usage: obj.test_invalid_return_type_in_get_iterator() without return types