langchain/vectorstores/docarray/base.py/DocArrayIndex/_get_doc_cls
class DocArrayIndex:    def _get_doc_cls(**embeddings_params: Any) -> Type["BaseDoc"]:
        """Get docarray Document class describing the schema of DocIndex."""
        from docarray import BaseDoc
        from docarray.typing import NdArray

        class DocArrayDoc(BaseDoc):
            text: Optional[str]
            embedding: Optional[NdArray] = Field(**embeddings_params)
            metadata: Optional[dict]

        return DocArrayDoc