class_docstr: A class to normalize data.
class_docstr_tok: ["A","class","to","normalize","data","."]
code: def exists(self):
      return tf.gfile.Exists(self._done_path)
  
imports: import io
  import os
  from absl import logging
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling the DataNormalizer obj's underlying member method code with example usage: obj.exists() and returns: tf