def init_dict_brackets(first_level_keys):
    """Initialise a  dictionary with one level

    Arguments
    ----------
    first_level_keys : list
        First level data

    Returns
    -------
    one_level_dict : dict
         dictionary
    """
    one_level_dict = {}
    for first_key in first_level_keys:
        one_level_dict[first_key] = {}
    return one_level_dict
