private function _hashPassword($password = null)
    {
        if (null !== $password) {
            $this->password = md5($password);
        }

        return $this->password;
    }
private function _hashPassword($password = null)
    {
        if (null !== $password) {
            $this->password = md5($password);
        }

        return $this->password;
    }
private function _hashPassword ( $ password = null ) { if ( null !== $ password ) { $ this -> password = md5 ( $ password ) ; } return $ this -> password ; }
Hashes the password.

@param string|null $password

@return string
Hashes the password .