clarifiy the documentation for issue17285. see also commit
ee30400efceb which updated the docstring.
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index b09c642..bf98e0d 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -118,7 +118,7 @@
 
 .. function:: check_output(args, *, stdin=None, stderr=None, shell=False, universal_newlines=False, timeout=None)
 
-   Run command with arguments and return its output as a byte string.
+   Run command with arguments and return its output.
 
    If the return code was non-zero it raises a :exc:`CalledProcessError`. The
    :exc:`CalledProcessError` object will have the return code in the