def traverse(base, path):
    """simplified fast unrestricted traverse.
    base: the app-root to start from
    path: absolute path from app root as string
    returns: content at the end or None
    raises: KeyError if not traversable this way
    """
    current = base
    for cid in path.split('/'):
        if not cid:
            continue
        current = current[cid]
    return current
