def getnode(self, config, arg):
        """Return the collection node of a file.

        :param config: :py:class:`_pytest.config.Config` instance, see
           :py:meth:`parseconfig` and :py:meth:`parseconfigure` to
           create the configuration.

        :param arg: A :py:class:`py.path.local` instance of the file.

        """
        session = Session(config)
        assert str(arg) not in '::'
        p = py.path.local(arg)
        config.hook.pytest_sessionstart(session=session)
        res = session.perform_collect([str(p)], genitems=False)[0]
        config.hook.pytest_sessionfinish(session=session, exitstatus=EXIT_OK)
        return res
dataset/ETHPy150Open pytest-dev/pytest/_pytest/pytester.py/Testdir.getnode/swapped operands of `not in`