[REF] Move function onto the processor class

[eileenmcnaughton]

Overview

Minor code cleanup

Before

Code in static function

After

Code moved to export object

Technical Details

I went to extract the function that determines fields off to be a function on the processor class
but moving this first simplifies it

Comments

The function itself is pretty rubbish - I would use early returns - but was less fussed about that

[civibot]

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[eileenmcnaughton]

unrelated fail