code: def viz_two_bundles(
      b1, b2, fname, c1=(1, 0, 0), c2=(0, 1, 0), interactive=False
  ):
      """Render and plot two bundles to visualize them.
  
      Parameters
      ----------
      b1 : Streamlines
          Bundle one to be rendered.
      b2 : Streamlines
          Bundle two to be rendered.
      fname: str
          Rendered scene is stored in a png file with that name.
      C1 : tuple, optional
          Color to be used for first bundle. Default red.
      C2 : tuple, optional
          Color to be used for second bundle. Default green.
      interactive : boolean, optional
          If True a 3D interactive rendering is created. Default is True.
  
      """
      ren = window.Scene()
      ren.SetBackground(1, 1, 1)
  
      actor1 = actor.line(b1, colors=c1)
      actor1.GetProperty().SetEdgeVisibility(1)
      actor1.GetProperty().SetRenderLinesAsTubes(1)
      actor1.GetProperty().SetLineWidth(6)
      actor1.GetProperty().SetOpacity(1)
      actor1.RotateX(-70)
      actor1.RotateZ(90)
  
      ren.add(actor1)
  
      actor2 = actor.line(b2, colors=c2)
      actor2.GetProperty().SetEdgeVisibility(1)
      actor2.GetProperty().SetRenderLinesAsTubes(1)
      actor2.GetProperty().SetLineWidth(6)
      actor2.GetProperty().SetOpacity(1)
      actor2.RotateX(-70)
      actor2.RotateZ(90)
  
      ren.add(actor2)
  
      if interactive:
          window.show(ren)
  
      window.record(ren, n_frames=1, out_path=fname, size=(1200, 1200))
      if interactive:
          im = plt.imread(fname)
          plt.figure(figsize=(10, 10))
          plt.imshow(im)
  
imports: from dipy.utils.optpkg import optional_package
label_desc: Use image node_id 2 for calling a global function with example usage: viz_two_bundles(b1, b2, fname, c1, c2, interactive) without return types