<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _check_instance(url, insecure):
 """Checks if there is an instance of Elasticsearch in url. Actually, it checks if GET on the url returns a JSON document with a field tagline "You know, for search", and a field version.number. :value url: url of the instance to check :value insecure: don't verify ssl connection (boolean) :returns: major version of Ellasticsearch, as string. """


        res = grimoire_con(insecure).get(url)
        if res.status_code != 200:
            logger.error("Didn't get 200 OK from url %s", url)
            raise ElasticConnectException
        else:
            try:
                version_str = res.json()['version']['number']
                version_major = version_str.split('.')[0]
                return version_major
            except Exception:
                logger.error("Could not read proper welcome message from url %s",
                             ElasticSearch.anonymize_url(url))
                logger.error("Message read: %s", res.text)
                raise ElasticConnectException