code: def fill_convexhull(bwimg):
      """
      hull = fill_convexhull(bwimg)
  
      Compute the convex hull and return it as a binary mask
  
      Parameters
      ----------
      bwimage : input image (interpreted as boolean)
  
      Returns
      -------
      hull : image of same size and dtype as `bwimg` with the hull filled in.
      """
  
      points = convexhull(bwimg)
      canvas = np.zeros_like(bwimg)
      black = 1 if bwimg.dtype == np.bool_ else 255
      fill_polygon(points, canvas, black)
      canvas[bwimg] = black
      return canvas
  
imports: from __future__ import division
  import numpy
  from .None import _convex
label_desc: Use image node_id 4 for calling a global function with example usage: fill_convexhull(bwimg) and returns: canvas