code: def _draw_polygon(ax, vertices, alpha=0.4):
      from matplotlib.patches import Polygon
      from matplotlib.collections import PatchCollection
      import matplotlib.pyplot as plt
  
      polygon = Polygon(vertices, closed=True)
      p = PatchCollection([polygon], match_original=True, alpha=alpha)
      polygon_object = ax.add_collection(p)
      plt.draw()
      return polygon_object
  
file_path: scikit-image/skimage/future/manual_segmentation.py
imports: from functools import reduce
  import numpy
  from ..draw import polygon
  from .._shared.version_requirements import require
label_desc: Use image node_id 2 for calling a global function with example usage: _draw_polygon(ax, vertices, alpha) and returns: polygon_object