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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 __create_preview_object_base(self, dct):
 """ The starting point for a preview of a future object. This is the object which will have future revisions iterated and applied to. :param dict dct: The starting object dictionary :return: The preview object id :rtype: str """

        if dct.get("_id"):
            del dct["_id"]

        preview_object_id = yield self.previews.insert(dct)

        raise Return(preview_object_id)