Markdown::getBlogByYearMonthId PHP Method

    public function getBlogByYearMonthId($yearMonthId)
    {
        $cacheKey = "getBlogByYearMonthId_" . $yearMonthId . ".gb";
        $blogList = $this->gbReadCache($cacheKey);
        if ($blogList === false) {
            $blogList = array();
            foreach ($this->blogs as $idx => $blog) {
                $_yearMonthId = date("Ym", strtotime($blog['date']));
                if ($yearMonthId == $_yearMonthId) {
                    array_push($blogList, $blog);
                }
            }
            $this->gbWriteCache($cacheKey, $blogList);
        }
        return $blogList;
    }