def execute(self, env, args):

        start = self._fuzzy_time_parse(args.start)
        if not start:
            raise errors.FocusError(u'Invalid start period provided')

        stats = self._get_stats(env.task, start)
        self._print_stats(env, stats)
Calculates 'beta' the backward variable.
dataset/ETHPy150Open xtrementl/focus/focus/plugin/modules/stats.py/Stats.execute--crossover with--dataset/ETHPy150Open QuantSoftware/QuantSoftwareToolkit/QSTK/qstklearn/hmm.py/calcbeta