code: def convex_hull(self):
          
          bnodes, nb, na, nt = _tripack.bnodes(self.lst, self.lptr, self.lend, self.npoints)
          return self._deshuffle_simplices(bnodes[:nb] - 1)
docs: Find the Convex Hull of the internal set of x,y points.
  
          Returns
          -------
           bnodes : array of ints
              indices corresponding to points on the convex hull