code: def bbox(self):
          
          bbs = [seg.bbox() for seg in self._segments]
          xmins, xmaxs, ymins, ymaxs = list(zip(*bbs))
          xmin = min(xmins)
          xmax = max(xmaxs)
          ymin = min(ymins)
          ymax = max(ymaxs)
          return xmin, xmax, ymin, ymax
docs: returns a bounding box for the input Path object in the form
          (xmin, xmax, ymin, ymax).