code: def corner(sankey):
      """Generate a corner link."""
      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,
      )
  
imports: import matplotlib.pyplot
  from matplotlib.sankey import Sankey
label_desc: Use image node_id 2 for calling a global function with example usage: corner(sankey) without return types