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:
        with open(self.f_sfp_present.format(port_num), 'r') as sfp_file:
            return 1 == int(sfp_file.read())
    except IOError as e:
        DBG_PRINT(str(e))
    return False