from keras.models import Sequential
from keras.layers.core import Dense, Activation

model = Sequential()
model.add(Dense(input_dim = 3, output_dim = 10))
model.add(Activation('relu'))
model.add(Dense(input_dim = 10, output_dim = 1))
model.add(Activation('sigmoid')

model.compile(loss = 'binary_crossentropy', optimizer = 'adam', class_mode = 'binary')

model.fit(x, y, nb_epoch = 1000, batch_size=32, epochs=1, verbose=1, callbacks=None, validation_split=0.0, validation_data=None, shuffle=True, class_weight=None, sample_weight=None, initial_epoch=1)
运行到最后一条的时候，总是提示以下错误，请问各位高手这是什么原因导致的？

ValueError: Invalid argument "class_mode" passed to K.function with Theano backend