code: def _is_rst_exists(entity):
      return os.path.exists(
          os.path.join(
              doc_source_dir,
              "reference",
              "generated",
              "{}.rst".format(entity),
          )
      )
  
file_path: chainer/docs/source/_autosummary_check.py
imports: import inspect
  import os
  import types
  import sphinx
  import chainer.functions
  import chainer.links
label_desc: Use image node_id 1 for calling a global function with example usage: _is_rst_exists(entity) and returns: os