我是lstm的新手，任何人都可以解释为什么我遇到此错误吗？
我的lstm模型-
def NNStructure（）：
input_text = tf.keras.Input((), dtype = tf.string, name = 'input_text')
initial_input= Embedding(vocab_size, 25, weights=
[embedding_matrix], input_length=50,trainable=False) (input_text)
lstm = LSTM(32, input_shape=(50,25))(initial_input)
secondary_input = Input(shape=(50,6))
merge = concatenate([lstm, secondary_input])(lstm)
first_dense = Dense(128, activation='relu')(merge)
second_dense=Dense(64, activation='relu')(first_dense)
output=Dense(1, activation='sigmoid')(second_dense)
model_glove1 = Model(inputs=[initial_input, secondary_input], outputs=output)
return model_glove1
model_glove1 = NNStructure（） model_glove1.compile（loss ='binary_crossentropy'，optimizer ='adam'，metrics = ['accuracy']） model_glove1.fit（x = [pad_seq，X_meta_train]，y = np.array（Y_train），batch_size = 32，epochs = 4，verbose = 1，validation_split = 0.2，shuffle = True）