code: def _get_forwarded(request, key):
          
          forwarded = request.headers.get('Forwarded', '')
          match = re.search(
              r'(?<={}=).+?(?=[\s,;]|$)'.format(key),
              forwarded,
              re.IGNORECASE)
  
          if match is not None:
              header = match.group(0)
  
              if header[0] == '"' and header[-1] == '"':
                  return header[1:-1]
  
              return header
  
          return request.headers.get('X-Forwarded-{}'.format(key.title()), '')
docs: Gets a forwarded value from the `Forwarded` header if present, or
          the equivalent `X-Forwarded-` header if not. If neither is present,
          returns an empty string.