The close_fds=<object . . .> in that signature seems fine to me. If you read the documentation, it says the default mode depends on the platform, and on other parameters. However I think the signature at <https://docs.python.org/release/3.6.4/library/subprocess.html#subprocess.Popen> should not show close_fds=True, because that is not necessarily the default on Windows.

It seems the default on Windows was changed to always True in 3.7, making it consistent across platforms and other parameters, thanks to Issue 19764. But the 3.7 documentation is quirky. “Changed in version 3.2: The default for ‘close_fds’ was changed from False to what is described above” refers to the 3.7 default when it was meant to refer to the 3.2–3.6 default.