def get_parent_uri(object_uri):
    """Get the parent URI for an object_uri.

    In order to be generic over any kind of resource hierarchy, we do
    this by string manipulation on the URI instead of trying to parse
    the URI, identify the parent resource, and generate a new URI.

    """
    path = object_uri.rsplit('/', 2)
    if len(path) < 3:
        return ''
    return path[0]
