def get_all_sources(self):
        """
        Returns:
            OrderedDict: all source file names in the hierarchy, paired with
                the names of their subpages.
        """
        if self.__all_sources is None:
            self.__all_sources = OrderedDict()
            self.walk(self.__add_one)
        return self.__all_sources
Returns:
            OrderedDict: all source file names in the hierarchy, paired with
                the names of their subpages.