docs: def loads(ast_str):
      """
      Create a Trace from a suitably compressed string.
      """
      data = zlib.decompress(ast_str)
      li = struct.unpack('<L', data[0:4])[0]
      lt = struct.unpack('<L', data[4:8])[0]
      n = data[8:8 + li].decode('utf-8')
      t = np.fromstring(data[8 + li:8 + li + lt])
      d = np.fromstring(data[8 + li + lt:])
  
      return Trace(d, t, name=n)