import json


def get_sub_suite(database, sub_suite_id):
    """Sub suite gets a sub suite by suite_id from database.

    :param database: The database to get sub suites from.
    :type database: :obj:`etos_lib.lib.database.Database`
    :param sub_suite_id: The suite ID of the sub suite in database.
    :type sub_suite_id: str
    :return: Sub suite or None.
    :rtype: dict
    """
    suite = database.read(sub_suite_id)
    if suite is None:
        return suite
    return json.loads(suite)