langchain/vectorstores/qdrant.py/Qdrant/_qdrant_filter_from_dict
class Qdrant:    def _qdrant_filter_from_dict(
        self, filter: Optional[MetadataFilter]
    ) -> Optional[rest.Filter]:
        from qdrant_client.http import models as rest

        if not filter:
            return None

        return rest.Filter(
            must=[
                condition
                for key, value in filter.items()
                for condition in self._build_condition(key, value)
            ]
        )