Dropout Training Parameter

use the functional format

inp = Input(shape=(X_len, 1))
x = LSTM(X_len, return_sequences = True)(inp)
x = Dropout(rate=0.2)(x, training=True)
x = LSTM(X_len)(x)
x = Dropout(rate=0.2)(x, training=True)
out = Dense(Y_len)(x)

model = Model(inp, out)
model.compile('adam', 'mse')
model.summary()