code: def _make_skeleton():
      skeleton = fod.KeypointSkeleton(
          labels=["point1", "point2", "nanpoint"],
          edges=[[0, 1], [1, 2]],
      )
  
      skeleton_key = "skeleton_key"
      return skeleton, skeleton_key
  
imports: from collections import defaultdict
  import os
  import eta.core.serial
  import fiftyone.core.odm.dataset
label_desc: Use image node_id 2 for calling a global function with example usage: _make_skeleton() and returns: skeleton,  skeleton_key