Python多行with语句

这在Python 3.9中已修复！

https://github.com/we-like-parsers/pegen/issues/229

with (Dummy() as a,        Dummy() as b,        # my comment explaining why I wanted Dummy() as c        Dummy() as c):    pass

这证明它有效：

Python 3.9.0a6 (default, Jun 20 2020, 14:52:53) Type 'copyright', 'credits' or 'license' for more informationIPython 7.15.0 -- An enhanced Interactive Python. Type '?' for help.In [3]: with (open('x')    ...:        as f):    ...:     pass    ...:      ---------------------------------------------------------------------------FileNotFoundError   Traceback (most recent call last)<ipython-input-3-47d5a51db08b> in <module>----> 1 with (open('x')      2        as f):      3     pass      4FileNotFoundError: [Errno 2] No such file or directory: 'x'In [4]:      Do you really want to exit ([y]/n)? ywPython 3.8.2 (default, May  8 2020, 20:08:31) Type 'copyright', 'credits' or 'license' for more informationIPython 7.15.0 -- An enhanced Interactive Python. Type '?' for help.In [1]: with (open('x')    ...:       as f):    ...:     pass          File "<ipython-input-1-e538abd13934>", line 2    as f):    ^SyntaxError: invalid syntax