Unsupported return value from function passed to Dataset.map()
问题 i am trying to preprocess and classify iris dataset using tensorflow piplines, but after the preprocessing i've got this error: Unsupported return value from function passed to Dataset.map(): (, NumericColumn(key='features', shape=(4,), default_value=None, dtype=tf.float32, normalizer_fn=None)) , i am stuck un there, il'll be happy for any helpe here's the complete code of the DNN import tensorflow_datasets as tfds from tensorflow.keras.optimizers import Adam data = tfds.load("iris", split