class_docstr: Descriptor used to define operations for delegating mixins.
  
  This class is designed to be assigned to the attributes (the delegating
  methods) defined by the OperationMixin. This class will create the method
  and mimic all the expected attributes for that method to appear as though
  it was originally designed on the class. The use of the descriptor pattern
  ensures that the method is only created the first time it is invoked, after
  which all further calls use the callable generated on the first invocation.
  
  Parameters
  ----------
  name : str
      The name of the operation.
  docstring_format_args : str
      The attribute of the owning class from which to pull format parameters
      for this operation's docstring.
  base_operation : str
      The underlying operation function to be invoked when operation `name`
      is called on the owning class.
code: def __get__(self, obj, owner=None):
      retfunc = _partialmethod(self._base_operation, op=self._name)
  
      # Required attributes that will exist.
      retfunc.__name__ = self._name
      retfunc.__qualname__ = ".".join([owner.__name__, self._name])
      retfunc.__module__ = self._base_operation.__module__
  
      if self._base_operation.__doc__ is not None:
          retfunc.__doc__ = self._base_operation.__doc__.format(
              cls=owner.__name__,
              op=self._name,
              **self._docstring_format_args,
          )
  
      retfunc.__annotations__ = (
          self._base_operation.__annotations__.copy()
      )
      retfunc.__annotations__.pop("op", None)
      retfunc_params = [
          v
          for k, v in inspect.signature(
              self._base_operation
          ).parameters.items()
          if k != "op"
      ]
      retfunc.__signature__ = inspect.Signature(retfunc_params)
  
      setattr(owner, self._name, retfunc)
  
      if obj is None:
          return getattr(owner, self._name)
      else:
          return getattr(obj, self._name)
  
imports: import inspect
label_desc: Use image node_id 2 for calling the Operation obj's underlying member method code with example usage: obj.__get__(obj, owner) and returns: getattr, getattr