class_docstr: Append one dimension of size one to the dataset shape.
code: def __init__(self, **kwargs):
      super().__init__(lambda x: tf.expand_dims(x, axis=-1), **kwargs)
  
imports: import tensorflow
  from autokeras import analysers
  from autokeras import keras_layers
  from autokeras import preprocessors
  from autokeras.engine import preprocessor
  from autokeras.utils import data_utils
label_desc: Use image node_id 1 to create a new AddOneDimension object from inherited base classes: LambdaPreprocessor with example: obj = AddOneDimension()