def flatten_dict_data(data, fun="{}/{}".format):
    """
    Flatten nested dictionary data into one layer dictionary.

    :return: Dictionary
    """
    if isinstance(data, dict):
        ret = {}
        for i in data:
            tmp = flatten_dict_data(data[i])
            if isinstance(tmp, dict):
                for j in tmp:
                    ret[fun(i, j)] = tmp[j]
            else:
                ret[i] = tmp
        return ret
    else:
        return data