code: def __init__(self, data_path):
      super(SintelData, self).__init__()
      self.data_path = data_path
      self.path_prefix = os.path.join(data_path, "flow")
      assert os.path.isdir(self.path_prefix), self.path_prefix
      self.flows = glob.glob(
          os.path.join(self.path_prefix, "*", "*.flo")
      )
  
file_path: tensorpack/examples/OpticalFlow/flownet2.py
imports: import argparse
  import glob
  import os
  import cv2
  from tensorpack import *
  from tensorpack.utils import viz
  import flownet_models
  from helper import Flow
label_desc: Use image node_id 1 to create a new SintelData object from inherited base classes: DataFlow with example: obj = SintelData(data_path)