questions about MTBO objective function

[zhaojingyao]

def objective(x, task):
if task == 0:
y = 0.5 * np.sin(3 * x[0]) * 4 * (x[0] - 1) * (x[0] + 2) + 0.5 * np.sin(3 * x[1]) * 4 * (x[1] - 1) * (x[1] + 2)
elif task == 1:
y = np.sin(3 * x[0]) * 4 * (x[0] - 1) * (x[0] + 2) + np.sin(3 * x[1]) * 4 * (x[1] - 1) * (x[1] + 2)
return y,y

lower = np.zeros(2)
upper = np.ones(2) * 6

results = mtbo(objective_function=objective,
lower=lower, upper=upper,
n_init=50, num_iterations=num_iterations, n_hypers=n_hypers,
rng=rng, output_path=output_path)

When I run this code, it tells me that "ValueError: array must not contain infs or NaNs".
Is there a problem with my definition of objective?