def extra(self, **kwargs: Any) -> Self:
        """
        Add extra keys to the request body. Mostly here for backwards
        compatibility.
        """
        s = self._clone()
        if "from_" in kwargs:
            kwargs["from"] = kwargs.pop("from_")
        s._extra.update(kwargs)
        return s

        Add extra keys to the request body. Mostly here for backwards
        compatibility.
        
elasticsearch/dsl/search_base.py