(original, derived)
return (not os.path.exists(derived))
Returns True if derivative is out-of-date wrt original,
    both of which are full file paths.
Returns True if derivative is out-of-date wrt original,
    both of which are full file paths.
Returns True if derivative is out - of - date wrt original both of which are full file paths .
def out_of_date(original, derived):
    """
    Returns True if derivative is out-of-date wrt original,
    both of which are full file paths.
    """
    return (not os.path.exists(derived))
def out_of_date ( original , derived ) : return ( not os . path . exists ( derived ) )