subprocess: Work around type checker limitation

Keyword argument is not accepted since it is used together with *args.

See also issue #153.

Author: JukkaL

python-lib/subprocess.py

@@ -505,7 +505,8 @@ def check_output(*popenargs, **kwargs):
     """
     if 'stdout' in kwargs:
         raise ValueError('stdout argument not allowed, it will be overridden.')
-    process = Popen(*popenargs, stdout=PIPE, **kwargs)
+    kwargs['stdout'] = PIPE
+    process = Popen(*popenargs, **kwargs)
     output, unused_err = process.communicate()
     retcode = process.poll()
     if retcode: