docstr: write many tracks together
          
docstr_tok: ["write","many","tracks","together"]
code: def write_tracks(self, tracks):
      """write many tracks together"""
  
      self.tracks.resize(
          self.tracks.shape[0] + tracks._data.shape[0], axis=0
      )
      self.tracks[-tracks._data.shape[0] :] = tracks._data
  
      self.offsets.resize(
          self.offsets.shape[0] + tracks._offsets.shape[0], axis=0
      )
      self.offsets[-tracks._offsets.shape[0] :] = (
          self.offsets[-tracks._offsets.shape[0] - 1]
          + tracks._offsets
          + tracks._lengths
      )
  
file_path: dipy/dipy/io/dpy.py
imports: import numpy
  import h5py
  from nibabel.streamlines import ArraySequence
label_desc: Use image node_id 4 for calling the Dpy obj's underlying member method code with example usage: obj.write_tracks(tracks) without return types