Thanks! I haven’t seen that type before, so I’m not sure I have any insight for you. My instinct though is that argument should be an array, while you’re currently passing in a dictionary. Have you tried this?

'argument’: [{'key1': 'val',
              'key2': 'val',
              'key3': 'val'}]

It’s been awhile since I did this, but I definitely spent time debugging deep into the source code to see how it was parsing my inputs and what XML it was generating — that may help you as well.

Would love to hear if you get a working solution to this, in case others run into it later!

Good luck!