def corner(sankey):
 prior = len(sankey.diagrams)
 sankey.add(flows=[1, (-1)], orientations=[0, 1], patchlabel=str(prior), facecolor='k', prior=(prior - 1), connect=(1, 0), alpha=0.5)

def corner ( sankey ) : prior = len ( sankey . diagrams ) sankey . add ( flows = [ 1 , ( - 1 ) ] , orientations = [ 0 , 1 ] , patchlabel = str ( prior ) , facecolor = 'k' , prior = ( prior - 1 ) , connect = ( 1 , 0 ) , alpha = 0.5 )
generate a corner link .