What are the defferences between DocTags and DocumentToken

[nkh0472]

I notice there are those two kind of functions conv_res.document.export_to_document_tokens() and conv_res.document.export_to_doctags().
And their output seems exactly the same.
So what's the difference between them?

PS:
The document makes me more confused. LOL

export_to_doctags

...
Exports the document content to a DocumentToken format.

export_to_document_tokens

...
Export to DocTags format.