environment/lib/python2.7/site-packages/IPython/config/configurable.py
def clear_instance(cls):
        """unset _instance for this class and singleton parents.
        """
        if not cls.initialized():
            return
        for subclass in cls._walk_mro():
            if isinstance(subclass._instance, cls):
                # only clear instances that are instances
                # of the calling class
                subclass._instance = None
def clear_instance(cls):
        """unset _instance for this class and singleton parents.
        """
        if not cls.initialized():
            return
        for subclass in cls._walk_mro():
            if isinstance(subclass._instance, cls):
                # only clear instances that are instances
                # of the calling class
                subclass._instance = None
unset _instance for this class and singleton parents.