ValueError: The size of the train_data (0) couldn't be smaller than batch_size (4). To solve this problem, set the batch_size smaller or increase the

train_data = object_detector.DataLoader.from_pascal_voc(
'ytfolder/train',
'ytfolder/train',
['pocachip', 'black_bean_milk'])

val_data = object_detector.DataLoader.from_pascal_voc(
'ytfolder/validate',
'ytfolder/validate',
['pocachip', 'black_bean_milk'])

spec = model_spec.get('efficientdet_lite0')

Help me I proceeded with these higher codes in order,

model = object_detector.create(train_data, model_spec=spec, batch_size=4, train_whole_model=True, epochs=20, validation_data=val_data)

but I keep getting errors at this part. How do we solve this?

ValueError: The size of the train_data (0) couldn't be smaller than batch_size (4). To solve this problem, set the batch_size smaller or increase the size of the train_data.