Pythonic way for `return (value == 'ok') ? 'ok' : 'nok' `

Possible Duplicate:
Ternary conditional operator in Python

I have this problem and have no idea to ask google for this:

(value == 'ok') ? 'ok' : 'not ok'

I mean that grammar with:

(expression) ? (return if <expresion> is true) : (return this value if <expresion> is false