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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 get_ubuntu_release_from_sentry(self, sentry_unit):
 """Get Ubuntu release codename from sentry unit. :param sentry_unit: amulet sentry/service unit pointer :returns: list of strings - release codename, failure message """

        msg = None
        cmd = 'lsb_release -cs'
        release, code = sentry_unit.run(cmd)
        if code == 0:
            self.log.debug('{} lsb_release: {}'.format(
                sentry_unit.info['unit_name'], release))
        else:
            msg = ('{} `{}` returned {} '
                   '{}'.format(sentry_unit.info['unit_name'],
                               cmd, release, code))
        if release not in self.ubuntu_releases:
            msg = ("Release ({}) not found in Ubuntu releases "
                   "({})".format(release, self.ubuntu_releases))
        return release, msg