code: def np2(theta_1, theta_2, phi_1, phi_2):
      temp = (
          np.sin((theta_2 - theta_1) / 2) ** 2
          + np.cos(theta_1)
          * np.cos(theta_2)
          * np.sin((phi_2 - phi_1) / 2) ** 2
      )
      return 2 * (np.arctan2(np.sqrt(temp), np.sqrt(1 - temp)))
  
label_desc: Use image node_id 1 for calling a global function with example usage: np2(theta_1, theta_2, phi_1, phi_2) and returns: unknown