public function removeSignedIdentifier($id)
    {
        Validate::canCastAsString($id, 'id');
        //var_dump($this->signedIdentifiers);
        for ($i = 0; $i < count($this->signedIdentifiers); ++$i) {
            if ($this->signedIdentifiers[$i]->getId() == $id) {
                array_splice($this->signedIdentifiers, $i, 1);
                return true;
            }
        }

        return false;
    }