code: def node(self):
          
  
          if self.node_class is None:
              raise ValueError("You have to create an ``Item`` by calling ``__init__`` with ``node_class`` argument"
                               " or by decorating a ``Node`` class.")
  
          node = self.node_class(*self.node_args, **self.node_kwargs)
          node.__item__ = self
  
          return node
docs: Create a :py:class:`Node` instance.
  
          All args and kwargs are forwarded to the node.
  
          :returns: a :py:class:`Node` instance