'Callback to Show progress bar.'

def __call__(self, param):

    count = param.nbatch
    filled_len = int(round(((self.bar_len * count) / float(self.total))))
    percents = math.ceil(((100.0 * count) / float(self.total)))
    prog_bar = (('=' * filled_len) + ('-' * (self.bar_len - filled_len)))
    logging.info('[%s]    %s%s\r', prog_bar, percents, '%')
