code: def _compute_bounding_box(points):
      
      (xmin, ymin, xmax, ymax) = (999999, 999999, -999999, -999999)
      for p in points:
          xmin = min(xmin, p[0])
          xmax = max(xmax, p[0])
          ymin = min(ymin, p[1])
          ymax = max(ymax, p[1])
      return (xmin, ymin, xmax, ymax)
docs: Given the list of coordinates (x,y), this procedure computes
      the smallest rectangle that covers all the points.