how to add noise

[quantumliang]

 class QLayer_input(tq.QuantumModule):
        def __init__(self):
            super().__init__()    
            self.n_wires = 4
            self.encoder = tq.GeneralEncoder(
        [   {'input_idx': [0], 'func': 'rx', 'wires': [0]},
            {'input_idx': [1], 'func': 'rx', 'wires': [1]},
            {'input_idx': [2], 'func': 'rx', 'wires': [2]},
            {'input_idx': [3], 'func': 'rx', 'wires': [3]},
        ])
            self.rx0 = tq.RX(has_params=True, trainable=True)
            self.rx1 = tq.RX(has_params=True, trainable=True)
            self.rx2 = tq.RX(has_params=True, trainable=True)
            self.rx3 = tq.RX(has_params=True, trainable=True)
            self.measure = tq.MeasureAll(tq.PauliZ)

        def forward(self, x):
            qdev = tq.QuantumDevice(n_wires=self.n_wires, bsz=x.shape[0], device=x.device)
            self.encoder(qdev, x)
            self.rx0(qdev, wires=0)
            self.rx1(qdev, wires=1)
            self.rx2(qdev, wires=2)
            self.rx3(qdev, wires=3)
            for k in range(self.n_wires):
                if k==self.n_wires-1:
                    tqf.cnot(qdev, wires=[k, 0]) 
                else:
                    tqf.cnot(qdev, wires=[k, k+1])
            `return(self.measure(qdev))`

this is a simple QNN， I want to know how to add noise in it? Are there any examples？