class_docstr: Special keyword value.
  
  The instance of this class may be used as the default value assigned to a
  deprecated keyword in order to check if it has been given a user defined
  value.
code: def __repr__(self):
      return "<no value>"
  
file_path: catboost/contrib/python/numpy/py2/numpy/_globals.py
imports: from __future__ import division, absolute_import, print_function
label_desc: Use image node_id 3 for calling the _NoValueType obj's underlying member method code with example usage: obj.__repr__() and returns: str