Need help in writing some code so i can re-use it in every module or class

[Roy Smith]

In article <mailman.7395.1393423618.18130.python-list at python.org>,
 Unix SA <d.joshi84 at gmail.com> wrote:

> Hello Experts,
> 
> I have requirement, like i want to use below command in python script.
> 
> <command> --username <username> --password <password>  <Command line
> arguments>
> 
> now my requirement is i want to write some class so i can re-use "<command>
> --username <username> --password <password>" part via importing as module
> or class  .. and re-use that in other module or classes .. so i dont have
> to write that in every module or classes ..
> 
> Now why i wan to do this is ... currently <command> we are using is going
> to change in near future to <command1>, so i dont have go to every module
> and change that command if i have written single module or class and re-use
> it in other ?

What you are talking about is a very common technique.  You write some 
code which abstracts the intent of an operation, but hides the 
implementation details.  Then, you can change the implementation without 
all the places it's called from having to be aware of the change.

So, it sounds like you want to write a function which accepts the two 
variable parts of the command, namely the username and password.  That 
function will then use call(), or one of its variants, from the 
subprocess module (http://docs.python.org/2/library/subprocess.html) to 
execute the actual command, inserting all the other boilerplate.

If, at some point in the future, you change which command you're 
calling, nothing but your function needs to change.