public function getRefreshToken(){
        if(isset($this->refresh_token) && !empty($this->refresh_token))  return $this->refresh_token;
        else throw new SdkException("The OAuth 2 Refresh Token is not set in the Access Token Object.");
    }
public function getRefreshToken(){
        if(isset($this->refresh_token) && !empty($this->refresh_token))  return $this->refresh_token;
        else throw new SdkException("The OAuth 2 Refresh Token is not set in the Access Token Object.");
    }
public function getRefreshToken ( ) { if ( isset ( $ this -> refresh_token ) && ! empty ( $ this -> refresh_token ) ) return $ this -> refresh_token ; else throw new SdkException ( "The OAuth 2 Refresh Token is not set in the Access Token Object." ) ; }
Return the refresh Token
@return String
Return the refresh Token