class_docstr: Raise this error instead of NotImplementedError for abstract methods
  while keeping compatibility with Python 2 and Python 3.
code: def __str__(self):
      if self.methodtype == "classmethod":
          name = self.class_instance.__name__
      else:
          name = self.class_instance.__class__.__name__
      msg = "This {methodtype} must be defined in the concrete class {name}"
      return msg.format(methodtype=self.methodtype, name=name)
  
imports: from pandas._libs.tslibs import OutOfBoundsDatetime
label_desc: Use image node_id 2 for calling the AbstractMethodError obj's underlying member method code with example usage: obj.__str__() and returns: msg