docstr: Returns the index of GPU (as in nvidia-smi).
docstr_tok: ["Returns","the","index","of","GPU","(","as","in","nvidia-smi",")","."]
code: def index(self):
      """
      Returns the index of GPU (as in nvidia-smi).
      """
      return self.entry["index"]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import json
  import platform
  import sys
  from datetime import datetime
  import psutil
  from ..gpu import pynvml
label_desc: Use image node_id 4 for calling the GPUStat obj's underlying member method code with example usage: obj.index() and returns: self