How to insert literal string values using wr.neptune.to_rdf_graph

[zicaden]

I am looking for a way to insert literal string from dataframe into neptune using sparql. The specific function wr.neptune.to_rdf_graph converts any literal value to default IRI "https://aws.amazon.com/neptune/default".

I have tried various means like @en, ^^xsd:string -even with full IRI such as "http://www.w3.org/2001/XMLSchema#" but none of them seem to provide the desired output. Even I made the dataframe object column dtype as string - from object - still no luck.

So with example:

what I expect to see

subject: http://example.org/books/book
predicate: http://example.org/books/author
object: "John Smith"

what i get to see:

subject: http://example.org/books/book
predicate: http://example.org/books/author
object: https://aws.amazon.com/neptune/default/John Smith