example.py

from keras import layers as L
from keras import models as M

inputs = L.Input((4, ))
output = L.Dense(3)(inputs)
model = M.Model(inputs, outputs)
model.compile('sgd', 'mse')

import numpy as np

x = np.random.random((5, 4))
y = np.random.random((5, 3))

model.fit(x, y)