docs: def change_angles(method, theta, tol=1e-10):
      """ Function used by all angle conversion functions (from_x_to_x_pi(...))"""
      try:
          theta_new = np.zeros(theta.shape)
          for i, thet in enumerate(theta):
              try:
                  # theta is vector
                  theta_new[i] = method(thet, tol)
              except:
                  # theta is matrix
                  for j, th in enumerate(thet):
                      try:
                          theta_new[i, j] = method(th, tol)
                      except:
                          # theta is tensor
                          for k, t in enumerate(th):
                              theta_new[i, j, k] = method(t, tol)
          return theta_new
      except:
          return method(theta, tol)