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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 enumerate_version_changelog(self, url, versions_estimated, timeout=15, headers={}):
 """ If we have a changelog in store for this CMS, this function will be called, and a changelog will be used for narrowing down which version is installed. If the changelog's version is outside our estimated range, it is discarded. @param url: the url to check against. @param versions_estimated: the version other checks estimate the installation is. @param timeout: the number of seconds to wait before expiring a request. @param headers: headers to pass to requests.get() """

        changelogs = self.vf.changelogs_get()
        ch_hash = None
        for ch_url in changelogs:
            try:
                ch_hash = self.enumerate_file_hash(url, file_url=ch_url,
                        timeout=timeout, headers=headers)
            except RuntimeError:
                pass

        ch_version = self.vf.changelog_identify(ch_hash)
        if ch_version in versions_estimated:
            return [ch_version]
        else:
            return versions_estimated