To clarify: Python 2.5 and higher support the with statement syntax, but not all classes that could benefit from it have the __enter__ and __exit__ methods.  So you don’t get a SyntaxError in Python 2.7 when you write “with Popen(...)”, but you get an AttributeError because Popen in 2.7 does not do its part to support context management.  The built-in open function, on the contrary, supports with in 2.5 and higher.