code: def test_center_and_transform():
      A = np.array([[1, 2, 3], [1, 2, 3.0]])
      streamlines = [A for _ in range(10)]
      streamlines2, center = center_streamlines(streamlines)
      B = np.zeros((2, 3))
      assert_array_equal(streamlines2[0], B)
      assert_array_equal(center, A[0])
  
      affine = np.eye(4)
      affine[0, 0] = 2
      affine[:3, -1] = -np.array([2, 1, 1]) * center
      streamlines3 = transform_streamlines(streamlines, affine)
      assert_array_equal(streamlines3[0], B)
  
imports: import warnings
  import types
  import numpy
  from numpy.linalg import norm
  import numpy.testing
  from dipy.testing.memory import get_type_refcount
  from dipy.testing import assert_arrays_equal
  from dipy.testing.decorators import set_random_number_generator
  from dipy.testing import assert_true
  from numpy.testing import assert_array_equal, assert_array_almost_equal, assert_raises, assert_allclose, assert_almost_equal, assert_equal
  from dipy.tracking.streamlinespeed import compress_streamlines, length, set_number_of_points
  from dipy.tracking.streamline import Streamlines
  from dipy.tracking.streamline import relist_streamlines, unlist_streamlines, center_streamlines, transform_streamlines, select_random_set_of_streamlines, select_by_rois, orient_by_rois, orient_by_streamline, values_from_volume, deform_streamlines, cluster_confidence
label_desc: Use image node_id 12 for calling a global function with example usage: test_center_and_transform() without return types