def init_dic_with(dic, key, default_value):
    """
    Inits dic[key] with default value, if key isn't in dic yet
    :param dic: A dictionary
    :param key: A key for dic
    :param default_value: Value to set dic[key] to if key isn't in dic
    :return: dic[key]
    """
    try:
        _ = dic[key]
    except KeyError:
        dic[key] = default_value
    return dic[key]
