code: def length(streamlines):
      """Calculate the lengths of many streamlines in a bundle.
  
      Parameters
      ----------
      streamlines : list
          Each item in the list is an array with 3D coordinates of a streamline.
  
      Returns
      -------
      Iterator object which then computes the length of each
      streamline in the bundle, upon iteration.
  
      """
      return map(metrics.length, streamlines)
  
imports: from collections import defaultdict, OrderedDict
  from functools import wraps
  from itertools import combinations, groupby
  from warnings import warn
  import numpy
  from nibabel.affines import apply_affine
  from scipy.spatial.distance import cdist
  from dipy.core.geometry import dist_to_corner
  from dipy.tracking import metrics
  from dipy.tracking.vox2track import _streamlines_in_mask
  from dipy.tracking._utils import _mapping_to_voxel, _to_voxel_coordinates
label_desc: Use image node_id 13 for calling a global function with example usage: length(streamlines) and returns: map