code: def length_python(xyz, along=False):
      xyz = np.asarray(xyz, dtype=np.float64)
      if xyz.shape[0] < 2:
          if along:
              return np.array([0])
          return 0
      dists = np.sqrt((np.diff(xyz, axis=0) ** 2).sum(axis=1))
      if along:
          return np.cumsum(dists)
      return np.sum(dists)
  
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 1 for calling a global function with example usage: length_python(xyz, along) and returns: np, int, np, np