code: def builder_inited(app):
          
          # Add this extension's _templates directory to Sphinx.
          templates_dir = os.path.join(os.path.dirname(__file__), '_templates')
          app.builder.templates.pathchain.insert(0, templates_dir)
          app.builder.templates.loaders.insert(0, SphinxFileSystemLoader(templates_dir))
          app.builder.templates.templatepathlen += 1
  
          # Add versions.html to sidebar.
          if '**' not in app.config.html_sidebars:
              app.config.html_sidebars['**'] = StandaloneHTMLBuilder.default_sidebars + ['versions.html']
          elif 'versions.html' not in app.config.html_sidebars['**']:
              app.config.html_sidebars['**'].append('versions.html')
docs: Update the Sphinx builder.
  
          :param sphinx.application.Sphinx app: Sphinx application object.