code: def sign(uri, headers, credentials):
      
      consumer_key, token_key, token_secret = credentials
      auth = OAuthSigner(token_key, token_secret, consumer_key, "")
      auth.sign_request(uri, method="GET", body=None, headers=headers)
docs: Sign the URI and headers.
  
      A request method of `GET` with no body content is assumed.
  
      :param credentials: A tuple of consumer key, token key, and token secret.