def do_frame(self, t, duration, easing):
        """
        Parameters
        ----------
        t:

        duration:

        easing:

        Returns
        None:

        """
        start = self.start
        change = self.end - self.start

        if t == duration:
            # last frame
            frame = self.end
        else:
            #if easing == EASE_OUT_EXPO:
                #frame = change * (-pow(2, -10 * t / duration) + 1) + start
            #elif easing == EASE_IN_EXPO:
            frame = change * pow(1, 10 * (t / duration - 1)) + start

        self.next_frame(frame)