src/Upwork/API/AuthTypes/OAuthPHPLib.php
protected function _setupAccessToken($verifier)
    {
        ApiDebug::p('requesting access token');

        $accessTokenInfo = array();

        $this->_getOAuthInstance();
        \OAuthRequester::requestAccessToken(
            self::$_apiKey,
            self::$_requestToken,
            0,
            'POST',
            array('oauth_verifier' => $verifier),
            self::_getCurlOptions()
        );

        $accessTokenInfo['oauth_token']         = $_SESSION['oauth_' . self::$_apiKey]['token'];
        $accessTokenInfo['oauth_token_secret']  = $_SESSION['oauth_' . self::$_apiKey]['token_secret'];

        ApiDebug::p('got access token info', $accessTokenInfo);

        self::$_accessToken     = $accessTokenInfo['oauth_token'];
        self::$_accessSecret    = $accessTokenInfo['oauth_token_secret'];

        return $accessTokenInfo;
    }
protected function _setupAccessToken($verifier)
    {
        ApiDebug::p('requesting access token');

        $accessTokenInfo = array();

        $this->_getOAuthInstance();
        \OAuthRequester::requestAccessToken(
            self::$_apiKey,
            self::$_requestToken,
            0,
            'POST',
            array('oauth_verifier' => $verifier),
            self::_getCurlOptions()
        );

        $accessTokenInfo['oauth_token']         = $_SESSION['oauth_' . self::$_apiKey]['token'];
        $accessTokenInfo['oauth_token_secret']  = $_SESSION['oauth_' . self::$_apiKey]['token_secret'];

        ApiDebug::p('got access token info', $accessTokenInfo);

        self::$_accessToken     = $accessTokenInfo['oauth_token'];
        self::$_accessSecret    = $accessTokenInfo['oauth_token_secret'];

        return $accessTokenInfo;
    }
Get access token

@param	string $verifier OAuth verifier, got after authorization
@access	protected
@return	array