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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 total_pages_in(self, leaderboard_name, page_size=None):
        '''
        Retrieve the total number of pages in the named leaderboard.

        @param leaderboard_name [String] Name of the leaderboard.
        @param page_size [int, nil] Page size to be used when calculating the total number of pages.
        @return the total number of pages in the named leaderboard.
        '''
        if page_size is None:
            page_size = self.page_size

        return int(
            math.ceil(
                self.total_members_in(leaderboard_name) /
                float(page_size)))