Sokil\Mongo\Structure::isModified PHP Method

    public function isModified($selector = null)
    {
        if (!$this->modifiedFields) {
            return false;
        }
        if (!$selector) {
            return (bool) $this->modifiedFields;
        }
        foreach ($this->modifiedFields as $modifiedField) {
            if (preg_match('/^' . $selector . '($|.)/', $modifiedField)) {
                return true;
            }
        }
        return false;
    }