code: public Token getToken(String code, String redirectUrl) throws IOException, WePayException {
  
  		TokenRequest request = new TokenRequest();
  		request.setClientId(key.getClientId());
  		request.setClientSecret(key.getClientSecret());
  		request.setRedirectUri(redirectUrl);
  		request.setCode(code);
  
  		return execute(null, request);
  	}
docs: Exchange a temporary access code for a (semi-)permanent access token
  @param code          'code' field from query string passed to your redirect_uri page
  @param redirectUrl  Where user went after logging in at WePay (must match value from getAuthorizationUri)
  @return json {"user_id":"123456","access_token":"1337h4x0rzabcd12345","token_type":"BEARER"}