def as_percent(self, percent):
        """ Return a string representing a percentage of this progress bar.
            BarSet('1234567890', wrapper=('[, ']')).as_percent(50)
            >>> '[12345     ]'
        """
        if not self:
            return self.wrap_str()

        length = len(self)
        # Using mod 100, to provide some kind of "auto reset". 0 is 0 though.
        percentmod = (int(percent) % 100) or min(percent, 100)
        index = int((length / 100) * percentmod)
        try:
            barstr = str(self[index])
        except IndexError:
            barstr = self[-1]

        return self.wrap_str(barstr)