code: def _build_package_finder(self, options, index_urls, session):
          
          return PackageFinder(
              find_links=options.find_links,
              index_urls=index_urls,
              allow_all_prereleases=options.pre,
              trusted_hosts=options.trusted_hosts,
              session=session,
          )
docs: Create a package finder appropriate to this list command.