This is a decorator function, which typically is used to modify the function or class it is decorating. But since we aren't modifying the test ( instead, we are just conditionally skipping it), the line "return lambda func: func" just says: "return the decorated function unmodified".

The unittest documentation includes a decorator example that uses this format:
http://docs.python.org/2.7/library/unittest.html#unittest-skipping