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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 get_page_children_dict(self, page_qs=None):
 """ Returns a dictionary of lists, where the keys are 'path' values for pages, and the value is a list of children pages for that page. """

        children_dict = defaultdict(list)
        for page in page_qs or self.pages_for_display:
            children_dict[page.path[:-page.steplen]].append(page)
        return children_dict