code: def setup_link_role(app):
      app.add_role("doi", doi_role, override=True)
      app.add_role("DOI", doi_role, override=True)
      app.add_role("arXiv", arxiv_role, override=True)
      app.add_role("arxiv", arxiv_role, override=True)
  
imports: from docutils import nodes, utils
  from sphinx.util.nodes import split_explicit_title
label_desc: Use image node_id 3 for calling a global function with example usage: setup_link_role(app) without return types