code: def verts_str(verts, pad=1):
      r
      if verts is None:
          return 'None'
      fmtstr = ', '.join(['%' + six.text_type(pad) + 'd' +
                          ', %' + six.text_type(pad) + 'd'] * 1)
      return ', '.join(['(' + fmtstr % vert + ')' for vert in verts])
docs: r""" makes a string from a list of integer verticies