but sometimes they are upside down.

I’ve got points for both eyes, and nose.
How can i calculate if after they rotation the nose will be below the eyes ?
So i can just add 180 degrees to it and fix the problem.

I am calculating my angle by following.

dx = left_eye.x - right_eye.x
dy = left_eye.y - right_eye.y

angle = np.arctan2(dx, dy)