code: def relpath(self, *segments):
      return os.path.join(self._base_dir, *segments)
  
imports: import os
  from unittest import mock
  import tensorflow
  from tfx.dsl.io import fileio
  from tfx.utils import io_utils
  from tensorflow.python.lib.io import file_io
label_desc: Use image node_id 2 for calling the IoUtilsTest obj's underlying member method code with example usage: obj.relpath() and returns: os