trinary: added parameter name
trinary: added parameter name

smalley/python,N-Parsons/exercism-python,pheanex/xpython,behrtam/xpython,smalley/python,pheanex/xpython,exercism/xpython,jmluy/xpython,mweb/python,mweb/python,behrtam/xpython,N-Parsons/exercism-python,exercism/python,exercism/python,exercism/xpython,jmluy/xpython