code: def test_normalized_3vec():
      vec = [1, 2, 3]
      l2n = np.sqrt(np.dot(vec, vec))
      assert_array_almost_equal(l2n, pf.norm_3vec(vec))
      nvec = pf.normalized_3vec(vec)
      assert_array_almost_equal(np.array(vec) / l2n, nvec)
      vec = np.array([[1, 2, 3]])
      assert_equal(vec.shape, (1, 3))
      assert_equal(pf.normalized_3vec(vec).shape, (3,))
  
file_path: dipy/dipy/tracking/tests/test_metrics.py
imports: import numpy
  import numpy.testing
  from numpy.testing import assert_equal, assert_array_almost_equal
  from dipy.tracking import metrics
  from dipy.tracking import distances
  from dipy.utils.deprecator import ExpiredDeprecationError
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 4 for calling a global function with example usage: test_normalized_3vec() without return types