code: def __str__(self):
      s = "Power series expansion of "
      s += str(self.holonomic)
      s += " about %s is not hypergeometric" % self.x0
      return s
  
file_path: sympy/sympy/holonomic/holonomicerrors.py
label_desc: Use image node_id 2 for calling the NotHyperSeriesError obj's underlying member method code with example usage: obj.__str__() and returns: s