def prio_dscp_map(duthosts, rand_one_dut_hostname):
    """
    This fixture reads the QOS parameters from SONiC DUT, and creates
    priority Vs. DSCP priority port map

    Args:
       duthosts (pytest fixture) : list of DUTs
       rand_one_dut_hostname (pytest fixture): DUT hostname

    Returns:
        Priority vs. DSCP map (dictionary, key = priority).
        Example: {0: [0], 1: [1], 2: [2], 3: [3], 4: [4] ....}
    """
    duthost = duthosts[rand_one_dut_hostname]
    config_facts = duthost.config_facts(host=duthost.hostname,
                                        source="running")['ansible_facts']

    if "DSCP_TO_TC_MAP" not in config_facts.keys():
        return None

    dscp_to_tc_map_lists = config_facts["DSCP_TO_TC_MAP"]
    if len(dscp_to_tc_map_lists) != 1:
        return None

    profile = dscp_to_tc_map_lists.keys()[0]
    dscp_to_tc_map = dscp_to_tc_map_lists[profile]

    result = {}
    for dscp in dscp_to_tc_map:
        tc = int(dscp_to_tc_map[dscp])
        result.setdefault(tc, []).append(int(dscp))

    return result