initilize dense layer weight.

def init_dense_weight(layer):
    '''initilize dense layer weight.
    '''
    units = layer.units
    weight = np.eye(units)
    bias = np.zeros(units)
    layer.set_weights(
        (add_noise(weight, np.array([0, 1])), add_noise(bias, np.array([0, 1])))
    )