How to use the execnet.PopenGateway function in execnet

def test_deprecation(recwarn, monkeypatch):
    execnet.PopenGateway().exit()
    assert recwarn.pop(DeprecationWarning)
    monkeypatch.setattr(socket, "socket", fails)
    py.test.raises(Exception, execnet.SocketGateway, "localhost", 8811)
    assert recwarn.pop(DeprecationWarning)
    monkeypatch.setattr(subprocess, "Popen", fails)
    py.test.raises(Exception, execnet.SshGateway, "not-existing")
    assert recwarn.pop(DeprecationWarning)

def test_deprecation(recwarn, monkeypatch):
    execnet.PopenGateway().exit()
    assert recwarn.pop(DeprecationWarning)
    monkeypatch.setattr(py.std.socket, 'socket', lambda *args: 0/0)
    py.test.raises(Exception, 'execnet.SocketGateway("localhost", 8811)')
    assert recwarn.pop(DeprecationWarning)
    monkeypatch.setattr(py.std.subprocess, 'Popen', lambda *args,**kwargs: 0/0)
    py.test.raises(Exception, 'execnet.SshGateway("not-existing")')
    assert recwarn.pop(DeprecationWarning)

def setup_class(cls):
        cls.gw = execnet.PopenGateway()
        cls.gw.remote_exec(
            "import py ; py.path.local(%r).pyimport()" %(__file__)
        )
        cls.gw.remote_init_threads(5)
        # we need the remote test code to import 

def setup_class(cls):
        cls.gw = execnet.PopenGateway()
        cls.gw.remote_exec(
            "import py ; py.path.local(%r).pyimport()" %(__file__)
        )
        cls.gw.remote_init_threads(5)
        # we need the remote test code to import