Pytest additional argument that allows tests run in parallel properly

I am using pytest and wish to use both -s (to disable all capturing) and -n NUM to allow multiple tests run at the same time. Each of them works well alone but when I use both of them together, I got error messages "redirected Stdin is pseudofile, has no fileno()", which I believe means that -s loses its function.

Would anyone tell me how to fix this error?

via Chebli Mohamed