'Estimate release schedule for Entry
:param entry:
:return: estimated date of released for the entry, None if it can\'t figure it out'

def estimate(self, entry):

    log.debug(entry['title'])
    estimators = [e.instance.estimate for e in plugin.get_plugins(interface='estimate_release')]
    for estimator in sorted(estimators, key=(lambda e: getattr(e, 'priority', plugin.DEFAULT_PRIORITY)), reverse=True):
        estimate = estimator(entry)
        if (estimate is not None):
            return estimate
