Added get_or_none wrapper for related_bill.
Added get_or_none wrapper for related_bill.

CivicTechTO/tor-councilmatic,CivicTechTO/tor-councilmatic,tor-councilmatic/tor-councilmatic,tor-councilmatic/tor-councilmatic,tor-councilmatic/tor-councilmatic,CivicTechTO/tor-councilmatic