os.path.splitext() and case sensitivity

[rbt]

Hi,

Is there a way to make os.path.splitext() case agnostic?

def remove_file_type(target_dir, file_type):
     for root, dirs, files in os.walk(target_dir):
         for f in files:
             if os.path.splitext(os.path.join(root, f))[1] in file_type:
                 pass

remove_file_type(sysroot, ['.tmp', '.TMP'])

As you can see, the way I do it now, I place file extensions in a list. 
However, I'd like to able just to say '.tmp' and for that to work on any 
type of file that has tmp (no matter the case) in the extension.

Many thanks!!!