ValueError: no signature found for builtin - cyfunction get_Model.locals.lambda

問題背景

使用cython編譯keras工程，編譯完成後運行時報錯

問題原因

神經網絡中存在keras.layers.Lambda層，對於構造參數function的lambda表示，cython無法讀取爲正常屬性

問題代碼及解決

# RNN layer
lstm_1 = LSTM(32, return_sequences = True, kernel_initializer = 'he_normal', name = 'lstm1')(inner)
lstm_1b = LSTM(32, return_sequences = True, go_backwards = True, kernel_initializer = 'he_normal',name = 'lstm1_b')(inner)  # (None, 64, 32)
# 此處爲原代碼，編譯爲pyd後執行報錯
# reversed_lstm_1b = Lambda(function = lambda inputTensor: K.reverse(inputTensor, axes = 1))(lstm_1b)
def rev(inputTensor):
    return K.reverse(inputTensor, axes = 1)
reversed_lstm_1b = Lambda(function = rev)(lstm_1b)
lstm1_merged = concatenate([lstm_1, reversed_lstm_1b])  # (None, 64, 64)
lstm1_merged = BatchNormalization()(lstm1_merged)