Here is one IN arg that I tried passing NULL to.
datatype=NUMERIC, argtype=IN, name=issueNO, ignore=yes, value=NULL
When I run, the error message is: Error wrapping value: issueNO:NULL - null, Cannot set: issueNO to NULL
I understand this is because I set the datatype as NUMERIC so it expects a number, so trying to find a way if I can pass NULL.
The other issues if I do this with a VARCHAR (string) type, it may treat NULL as "NULL" (string) and not null.