protected function _setNumArgs($numArgs)
    {
        $numArgs = $this->_normalizeInt($numArgs);

        if ($numArgs < 0) {
            throw $this->_createOutOfRangeException(
                $this->__('Number of arguments cannot be smaller than zero'), null, null, $numArgs
            );
        }

        $this->numArgs = $numArgs;
    }