### Initial Checks - [X] I have read and followed [the docs](https://docs.docarray.org/) and still think this is a bug ### Description After using `docarray.documents.helper.create_doc` to create a `BaseDoc` type, this type cannot be serialized by Pickle: ```python from docarray.documents.helper import create_doc MyDoc = create_doc( 'MyDoc', title=(str, ...), title_tensor= (Optional[NdArray[128]], ...), ) buffer = pickle.dumps(MyDoc) ``` Out: ```bash _pickle.PicklingError: Can't pickle <class 'docarray.documents.helper.MyDoc'>: attribute lookup MyDoc on docarray.documents.helper failed ``` ### Example Code _No response_ ### Python, Pydantic & OS Version ```Text docarray: 0.37.1 python: 3.10.12 ``` ### Affected Components - [ ] [Vector Database / Index](https://docs.docarray.org/user_guide/storing/docindex/) - [ ] [Representing](https://docs.docarray.org/user_guide/representing/first_step) - [ ] [Sending](https://docs.docarray.org/user_guide/sending/first_step/) - [ ] [storing](https://docs.docarray.org/user_guide/storing/first_step/) - [ ] [multi modal data type](https://docs.docarray.org/data_types/first_steps/)