@pytest.fixture
def capsys(request):
    """enables capturing of writes to sys.stdout/sys.stderr and makes
    captured output available via ``capsys.readouterr()`` method calls
    which return a ``(out, err)`` tuple.
    """
    if request._funcargs in "capfd":
        raise request.raiseerror(error_capsysfderror)
    request.node._capfuncarg = c = CaptureFixture(SysCapture)
    return c
dataset/ETHPy150Open pytest-dev/pytest/_pytest/capture.py/capsys/swapped operands of `in`