code: def setup(self):
      self.dense_vol = np.zeros((100, 100, 100))
      self.dense_vol[:] = 10
      self.sparse_vol = np.zeros((100, 100, 100))
      self.sparse_vol[0, 0, 0] = 1
  
file_path: dipy/benchmarks/benchmarks/bench_segment.py
imports: import numpy
  from dipy.data import get_fnames
  from dipy.io.streamline import load_tractogram
  from dipy.tracking.streamline import Streamlines, set_number_of_points
  from dipy.segment.metricspeed import Metric
  from dipy.segment.clustering import QuickBundles
  from dipy.segment.mask import bounding_box
label_desc: Use image node_id 1 for calling the BenchMask obj's underlying member method code with example usage: obj.setup() without return types