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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update(self, url, cache_info=None):
 """ Update cache information for url :param url: Update for this url :type url: str | unicode :param cache_info: Cache info :type cache_info: floscraper.models.CacheInfo :rtype: None """

        key = hashlib.md5(url).hexdigest()
        access_time = None
        if not cache_info:
            cache_info = CacheInfo()
        if not access_time:
            cache_info.access_time = now_utc()
        self._cache_meta_set(key, cache_info.to_dict())