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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 set_doc_ids(self, doc_ids):
 """ Build xml documents from a list of document ids. Args: doc_ids -- A document id or a lost of those. """

        if isinstance(doc_ids, list):
            self.set_documents(dict.fromkeys(doc_ids))
        else:
            self.set_documents({doc_ids: None})