Can't install gevent and msgpack

> ValueError: ("Expected ',' or end-of-list in", "cffi >= 1.11.5 ; sys_platform ==
> 'win32' and platform_python_implementation == 'CPython'", 'at', " ; sys_platfor
> m == 'win32' and platform_python_implementation == 'CPython'")

Start by reproducing the reported installation failure for gevent and msgpack, then inspect the dependency declarations that produce the cffi platform marker. Confirm whether the parser error is still reproducible and document the supported installation result before making any change.

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