code: def group_useful_matrix(theta, elem_33=1.0):
      return gs.array(
          [
              [gs.cos(theta), -gs.sin(theta), 2.0],
              [gs.sin(theta), gs.cos(theta), 3.0],
              [0.0, 0.0, elem_33],
          ]
      )
  
imports: import geomstats.backend
  from geomstats.test.data import TestData
  from .base import LevelSetTestData
  from .invariant_metric import InvariantMetricMatrixTestData
  from .lie_group import LieGroupTestData, MatrixLieGroupTestData
  from .mixins import ProjectionMixinsTestData
label_desc: Use image node_id 1 for calling a global function with example usage: group_useful_matrix(theta, elem_33) and returns: gs