public function setIncludePath($includePath)
    {
        if (!file_exists($includePath)) {
            throw new \InvalidArgumentException(
                sprintf('Path "%s" declared as namespace\'s "%s" include path does not exist!', $includePath, $this->getNamespace())
            );
        }
        if (!is_dir($includePath)) {
            throw new \InvalidArgumentException(
                sprintf('Path "%s" declared as namespace\'s "%s" include path is not a directory!', $includePath, $this->getNamespace())
            );
        }
        $this->_includePath = realpath($includePath);
        return $this;
    }