public function memberInfo($email_id, $email_identifier = 'email')
    {
        if (!in_array($email_identifier, array("email", "euid", "leid")))
            throw new InvalidArgumentException('email identifier should be one of ("email","euid","leid")');
        $email_ids = array();
        if (is_array($email_id))
        {
            foreach ($email_id as $email) {
                $email_ids[] = array($email_identifier => $email);
            }
        } else {
            $email_ids[] = array($email_identifier => $email_id);
        }
        $payload = array(
            'id' => $this->listId,
            'emails' => $email_ids
        );
        $apiCall = 'lists/member-info';
        $data = $this->requestMonkey($apiCall, $payload);
        $data = json_decode($data, true);
        if (isset($data['error']))
            throw new MailchimpAPIException($data);
        else
            return isset($data) ? $data : false;
    }