#NEWLINE# def _get_f( self ) : #NEWLINE# #INDENT# x1 = chainer . Variable ( self . x1 ) #NEWLINE# x2 = chainer . Variable ( self . x2 ) #NEWLINE# ( y1 , y2 ) = self . f ( x1 , x2 ) #NEWLINE# f = y1 . creator #NEWLINE# return ( f , x1 , y2 )