Y = Dense(2)(Y)Z = LSTM(128, return_sequences=False)(X)Z = Dense(2)(Z)M = concatenate([Y, Z,Y+Z])M=Dense(4)(M)M = Dense(2)(M)# 添加softmax激活函数M = Activation('softmax')(M)# 创建将sentence_indices转换为X的模型实例model = Model(inputs=sentence_indices, outputs=M)return model这是我的代码块。这里我给出的是部分代码。我希望使用 M = concatenate([Y, Z]) 来合并层，这样工作得很好。然后我想在 Dense 层中添加更多的变量，所以我添加了 M = concatenate([Y, Z,Y+Z])；然而，这并不工作。它给我这个错误：
Traceback (most recent call last): File "/home/sathiyakugan/PycharmProjects/internal-apps/apps/support-tools/EscalationApp/IMDBmodified.py", line 213, in <module> model = buildModel((maxLen,), word_to_vec_map, word_to_index) File "/home/sathiyakugan/PycharmProjects/internal-apps/apps/support-tools/EscalationApp/IMDBmodified.py", line 206, in buildModel model = Model(inputs=sentence_indices, outputs=M) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/legacy/interfaces.py", line 91, in wrapper return func(*args, **kwargs) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 91, in __init__ self._init_graph_network(*args, **kwargs) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 235, in _init_graph_network self.inputs, self.outputs) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1412, in _map_graph_network tensor_index=tensor_index) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1399, in build_map node_index, tensor_index) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1399, in build_map node_index, tensor_index) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1399, in build_map node_index, tensor_index) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1399, in build_map node_index, tensor_index) File "/home/sathiyakugan/PycharmProjects/Python/venv/lib/python3.5/site-packages/keras/engine/network.py", line 1371, in build_map node = layer._inbound_nodes[node_index]AttributeError: 'NoneType' object has no attribute '_inbound_nodes' 您能帮我解决这个问题吗？
回答：
A = add([Y, Z])M = concatenate([Y, Z, A])