code: def download_data(self, source_url, out_dir):
      raise NotImplementedError
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  import sys
  import tf_euler
  from euler.tools.generate_euler_data import EulerGenerator
label_desc: Use image node_id 9 for calling the DataSet obj's underlying member method code with example usage: obj.download_data(source_url, out_dir) without return types