More examples
-------------

Objects that have a __del__ method

    >>> class Nondestructible(list):
    ...     def __del__(self):
    ...         pass

    >>> x = Nondestructible()
    >>> y = []
    >>> z = []
    >>> x.append(y)
    >>> y.append(z)
    >>> z.append(x)
    >>> del x, y, z

    >>> import objgraph
    >>> objgraph.show_backrefs(objgraph.by_type('Nondestructible'), filename='finalizers')

.. image:: finalizers.png