def get_sysnet_mac(sysdir: str) ->str:
    """Determine MAC address for a device

    :param: sysdir: path to device /sys directory
    :type: str
    :returns: MAC address of device
    :rtype: str
    """
    mac_addr_file = sysdir + '/address'
    with open(mac_addr_file, 'r') as f:
        read_data = f.read()
    return read_data.strip()
