class_docstr: Most of ImageNet pretrained models are inherited from this class
  so that it provides some common interfaces.
docstr: Returns category names of 1000 ImageNet classes.
docstr_tok: ["Returns","category","names","of","1000","ImageNet","classes","."]
code: def category_names(self):
      """
      Returns category names of 1000 ImageNet classes.
      """
      if hasattr(self, "_category_names"):
          return self._category_names
      with open(
          os.path.join(os.path.dirname(__file__), "category_names.txt"),
          "r",
      ) as fd:
          self._category_names = fd.read().splitlines()
      return self._category_names
  
file_path: nnabla/python/src/nnabla/models/imagenet/base.py
imports: from __future__ import absolute_import
  import nnabla
  from nnabla.utils.nnp_graph import NnpLoader
  from ..utils import *
label_desc: Use image node_id 1 for calling the ImageNetBase obj's underlying member method code with example usage: obj.category_names() and returns: self, self