code: def test_from_python():
      with pytest.raises(RuntimeError) as excinfo:
          Matrix(np.array([1, 2, 3]))  # trying to assign a 1D array
      assert str(excinfo.value) == "Incompatible buffer format!"
  
      m3 = np.array([[1, 2, 3], [4, 5, 6]]).astype(np.float32)
      m4 = Matrix(m3)
  
      for i in range(m4.rows()):
          for j in range(m4.cols()):
              assert m3[i, j] == m4[i, j]
  
      cstats = ConstructorStats.get(Matrix)
      assert cstats.alive() == 1
      del m3, m4
      assert cstats.alive() == 0
      assert cstats.values() == ["2x3 matrix"]
      assert cstats.copy_constructions == 0
      # assert cstats.move_constructions >= 0  # Don't invoke any
      assert cstats.copy_assignments == 0
      assert cstats.move_assignments == 0
  
imports: import pytest
  from pybind11_tests import Matrix, ConstructorStats
label_desc: Use image node_id 1 for calling a global function with example usage: test_from_python() without return types