String arrays with values containing commas

[gmweinberg]

I have discovered that for fields that are get request "string arrays", to get them to work properly you don't use a python list, you use a comma -delimited string for the values. For example, in FulfillmentInbound.prep_instructions if you actually use a pylon list for SellerSKUList you only get the value back for the last value in the list, but if you say SellerSKUList = ",".join(SellerSKUList) you get values for all you seller skus.
Unless the skus themselves contain commas, in which case I am screwed, amazon is treating the comma as a separator and telling me the fragments are nonexistent skus.
I didn't really see that use a comma delimiter in the amazon docs, it was more or less just a lucky guess. I've tried to escape or quote the commas in various ways without success, I don't know if it can be done or not.

So I have 2 questions:

1. Has anyone else here encountered this problem and found a solution?
2. Is it worthwhile adding lines like
   If type( SellerSKUList) == list:
   SellerSKUList =",".join(SellerSKULis)
   in this api? I think it would make it easier for people who haven't figured out yet that that's what you need to do and shouldn't break existing code.