Store parent object in attributes.

[Skadabucci]

Hello,
I think a valuable feature would be the ability to access a parent object given any yang path object.

Example:

Given a room object

>>> room
<pyangbind.lib.yangtypes.YANGBaseClass object at 0x21eb430>
>>> room._yang_path()
u"/domains/domain[name='foo']/sites/site[name='bar']/rooms/room[name='scotty']"

I would like the ability to access the site object that has the key named bar like so:

>>> room.parent().parent().name
u'bar'

Current Work Around

We have a class that wraps our graph, within that we have the following method:

    def get_parent(self, object, generations=1):
        # Split up the yang path and remove empty strings
        path = [x for x in object._yang_path().split('/') if x]
        # Transform parts of the path from: domain[name='foo'] to: domain['foo']
        path = [re.sub(r"(.+?)\[.+='(.+)'\]", "\g<1>['\g<2>']", x) for x in path]
        # Remove the number of generations from the path
        path = path[:generations * -1]
        # create the string and evaluate it
        return eval('self.graph.{}'.format('.'.join(path)))

This works, but it would be super helpful having this baked into pyyangbind.

>>> graph_wrapper.get_parent(room, generations=2).name
u'bar'

In this workaround self holds an attribute graph that stores the value of my actual graph generated from pyyangbind code. Note that I have not tested this with objects that have multiple keys.