code: def sph_coords_to_pose(theta, psi):
          
          # rotate about the z and y axes individually
          rot_z = RigidTransform.z_axis_rotation(theta)
          rot_y = RigidTransform.y_axis_rotation(psi)
          R = rot_y.dot(rot_z)
          return RigidTransform(rotation=R)
docs: Convert spherical coordinates to a pose.
          
          Parameters
          ----------
          theta : float
              azimuth angle
          psi : float
              elevation angle
  
          Returns
          -------
          :obj:`RigidTransformation`
              rigid transformation corresponding to rotation with no translation