I am writing a program to calculate light refraction using snell's law, however, when I run the program it prints -0.7076118148 rather than the correct value of 22
import numpy as np
theta_1 = 30
n1 = 1
n2 = 1.33
theta_2 = np.arcsin(n1 / n2 * np.sin(theta_1))
print(theta_2)