docs: def opensearch(request):
      """
      Return opensearch.xml.
      """
  
      contact_email = settings.CONTACT_EMAIL
      short_name = settings.SHORT_NAME
      description = settings.DESCRIPTION
      favicon_width = settings.FAVICON_WIDTH
      favicon_height = settings.FAVICON_HEIGHT
      favicon_type = settings.FAVICON_TYPE
      favicon_file = settings.FAVICON_FILE
      url = "{url}?{querystring}{{searchTerms}}".format(**{
          "url": request.build_absolute_uri(reverse(settings.SEARCH_URL)),
          "querystring": settings.SEARCH_QUERYSTRING,
      })
      input_encoding = settings.INPUT_ENCODING.upper()
  
      return render_to_response("opensearch/opensearch.xml", context=locals(), content_type="application/opensearchdescription+xml")