如何使用keras预测两个数值列？

import numpy as np
from keras.models import Sequential
from keras.layers import Dense

# 假设有两个数值列作为输入特征
input_data = np.array([[1, 2], [3, 4], [5, 6], [7, 8]])
# 假设有一个数值列作为目标值
target_data = np.array([3, 7, 11, 15])

model = Sequential()
model.add(Dense(10, input_dim=2, activation='relu'))
model.add(Dense(1, activation='linear'))

model.compile(loss='mean_squared_error', optimizer='adam')

model.fit(input_data, target_data, epochs=100, batch_size=1)

predictions = model.predict(input_data)