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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(self, obj_id):
 """ Get a document or a page using its ID Won't instantiate them if they are not yet available """

        if BasicPage.PAGE_ID_SEPARATOR in obj_id:
            (docid, page_nb) = obj_id.split(BasicPage.PAGE_ID_SEPARATOR)
            page_nb = int(page_nb)
            return self._docs_by_id[docid].pages[page_nb]
        return self._docs_by_id[obj_id]