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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def scroll(self, direction='vertical', percent=0.6, duration=2.0):
 """ Scroll from the lower part to the upper part of the entire screen. Args: direction (:py:obj:`str`):
 scrolling direction. "vertical" or "horizontal" percent (:py:obj:`float`):
 scrolling distance percentage of the entire screen height or width according to direction duration (:py:obj:`float`):
 time interval in which the action is performed """


        if direction not in ('vertical', 'horizontal'):
            raise ValueError('Argument `direction` should be one of "vertical" or "horizontal". Got {}'
                             .format(repr(direction)))

        start = [0.5, 0.5]
        half_distance = percent / 2
        if direction == 'vertical':
            start[1] += half_distance
            direction = [0, -percent]
        else:
            start[0] += half_distance
            direction = [-percent, 0]

        return self.swipe(start, direction=direction, duration=duration)