When run without arguments, siet.py should print arg summary

[jtesta]

If siet.py is run without arguments, instead of printing a summary of arguments, an error message is dumped:

# python siet.py 
Traceback (most recent call last):
  File "siet.py", line 350, in <module>
    main()
  File "siet.py", line 298, in main
    change_tftp(args.mode, current_ip)
  File "siet.py", line 206, in change_tftp
    my_ip = conn_with_client(None, current_ip)
  File "siet.py", line 129, in conn_with_client
    conn_with_host.connect((ip, 4786))
  File "/usr/lib/python2.7/socket.py", line 228, in meth
    return getattr(self._sock,name)(*args)
TypeError: coercing to Unicode: need string or buffer, NoneType found
-= DvK =- TFTP server 2017(p)
root@ubuntu1804lts:~/SIET# [INFO]: Directory already exists. OK.
[INFO]: binding socket .. ok