def dict_get_nested(d, keys, alt_ret):
    """Get a nested dictionary entry given a list of keys.

    Equivalent to d[keys[0]][keys[1]]...etc.

    Args:
        d (dict): nested dictionary to search.
        keys (list): keys to search one by one.
        alt_ret: returned if the specified item is not found.

    Returns:
          item matching the chain of keys in d.

    """
    item = d.get(keys[0], alt_ret)
    for k in keys[1:]:
        item = item.get(k, alt_ret)
    return item