bind: refactor genFunc
bind: refactor genFunc

Change-Id: Icfcce2f87dc50fd0eef0cbc12ecc4484401c465d

ericsnowcurrently/gopython-gopy,lifei/gopy,go-python/gopy-gen,go-python/gopy,kellrott/gopy,kellrott/gopy,ericsnowcurrently/gopython-gopy,go-python/gopy-gen,go-python/gopy,lifei/gopy