In SYNR-1280, and anywhere we expect a list of items, and users enter a single value, they will see similar error that the backend JSON adapter thrown.
This ticket is to explore the option of the following conversion rule:
A vector of a single value in R will be converted to a single value in Python
A list of a single value in R will be converted to a list of a single value in Python
If we can implement this conversion rule in PythonEmbedInR, anywhere user see the JSON array conversion error, they can replace their <value> with list(<value>) to change from a single value input to a list of one value input.