code: def __len__(self):
      return len(self.x)
  
file_path: BigDL/python/nano/src/bigdl/nano/deps/openvino/tf/dataloader.py
imports: from openvino.tools.pot import DataLoader
  import tensorflow
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 3 for calling the KerasOpenVINODataLoader obj's underlying member method code with example usage: obj.__len__() and returns: len