newbie help

[<oop...@ne...>]

hi 
please some one help i am new to python
i want to perform a modify operation on the cn attribute of th dn
"mail=11...@nd...,dc=ndd,dc=com"
for that my script is 


#!/usr/bin/python 
import getpass
import _ldap

l.simple_bind_s(login_dn,login_pw)
try:
    
    dn="mail=11...@nd...,dc=ndd,dc=com"
    print "adding    ",repr(dn)
    
    
        l.modify_s(dn,_ldap.MOD_REPLACE,[('cn',["fgs"])])
                
except _ldap.LDAPError:
       pass


l.unbind()


when i run the script i get the following error


adding     'mail=11...@nd...,dc=ndd,dc=com'
Traceback (innermost last):
  File "mod.py", line 19, in ?
    l.modify_s(dn,_ldap.MOD_REPLACE,[('cn',["fgs"])])
TypeError: function requires exactly 2 arguments; 3 given


pl tell me the correct syntax of how i should do ir



ritu