Q:

Python if statement without indent

I'm working with an inherited Python program, which runs OK, but does not have correct Python indenting.  
if not arg_o:
print >> sys.stderr, 'Output file needed.'
print >> sys.stderr, usage
exit()

What is going on here? Shouldn't the code below the if be indented?
SOLVED
See the accepted answer. It turns out that TextMate was not properly displaying the tabs, which is a worry. When opened in Vim it was indented properly.

A:

After checking the file - MPprimer.py - from the code found here .
I can see the following lines in it -
if not arg_o:
    print >> sys.stderr, 'Output file needed.'
    print >> sys.stderr, usage
    exit()

Starting at line 175 . The issue is that this script mixes tabs and spaces.
The line 175 - if not arg_o: -  uses 4 spaces as indentation.
whereas , the next line, line 176 - print >> sys.stderr, 'Output file needed.' - uses a tab as indentation.
In Python 2.x , tabs and spaces can be mixed, but a tab is internally represented by 8 spaces.
But in some editors (like Notepad ++ , in my System) , tab is only interpreted as 4 spaces. So even though in those editors they look like they are not correctly indented, they are actually correctly indented , according to python.
Please note, it is not a good practice to mix tabs and spaces, Python 3.x , would error out if you mix them in the same script.

