docs: def load_template_source(template_name, template_dirs=None):
      """Template loader that loads templates from a ZIP file."""
      template_zipfiles = getattr(settings, "TEMPLATE_ZIP_FILES", [])
  
      # Try each ZIP file in TEMPLATE_ZIP_FILES.
      for fname in template_zipfiles:
          try:
              z = zipfile.ZipFile(fname)
              source = z.read(template_name)
          except (IOError, KeyError):
              continue
          z.close()
          # We found a template, so return the source.
          template_path = "%s:%s" % (fname, template_name)
          return (source, template_path)
  
      # If we reach here, the template couldn't be loaded
      raise TemplateDoesNotExist(template_name)