code: def _logm_expm_data(self, func_name="linalg.logm"):
      arrays = [
          Matrices.to_diagonal(rand(3, 3)),
      ]
      return [dict(func_name=func_name, a=array) for array in arrays]
  
file_path: geomstats/tests/tests_geomstats/test_backend/data/backend.py
imports: import geomstats.backend
  from geomstats.geometry.matrices import Matrices
  from geomstats.geometry.spd_matrices import SPDMatrices
  from geomstats.geometry.special_orthogonal import SpecialOrthogonal
  from geomstats.geometry.symmetric_matrices import SymmetricMatrices
  from geomstats.test.data import TestData
label_desc: Use image node_id 2 for calling the BackendTestData obj's underlying member method code with example usage: obj._logm_expm_data(func_name) and returns: unknown