code: def unique():
      """Creates a `Dataset` from another `Dataset`, discarding duplicates.
  
      Use this transformation to produce a dataset that contains one instance of
      each unique element in the input. For example:
  
      ```python
      dataset = tf.data.Dataset.from_tensor_slices([1, 37, 2, 37, 2, 1])
  
      # Using `unique()` will drop the duplicate elements.
      dataset = dataset.apply(tf.data.experimental.unique())  # ==> { 1, 37, 2 }
      ```
  
      Returns:
        A `Dataset` transformation function, which can be passed to
        `tf.data.Dataset.apply`.
      """
  
      def _apply_fn(dataset):
          return dataset.unique()
  
      return _apply_fn
  
label_desc: Use image node_id 1 for calling a global function with example usage: unique() and returns: _apply_fn, dataset