def METHOD_NAME(self, port_num):
    # Check for invalid port_num
    if port_num < self.port_start or port_num > self.port_end:
        return False
    try:
        reg_file = open("/sys/devices/platform/delta-ag5648-cpld.0/sfp_lpmode")
    except IOError as e:
        print("Error: unable to open file: %s" % str(e))
    content = reg_file.readline().rstrip()
    # content is a string containing the hex representation of the register
    reg_value = int(content, 16)
    # Mask off the bit corresponding to our port
    mask = (1 << port_num)
    # LPMode is active high
    if reg_value & mask == 0:
        return False
    return True