@classmethod
  def _GetInstance(cls):
    op = Operation.GetCurrent()
    lock_tracker = op.context.get('viewpoint_lock_tracker')
    if lock_tracker is None:
      lock_tracker = ViewpointLockTracker()
      op.context['viewpoint_lock_tracker'] = lock_tracker

    return lock_tracker
Ensures that a viewpoint lock tracker has been created and attached to the current
dataset/ETHPy150Open viewfinderco/viewfinder/backend/db/viewpoint_lock_tracker.py/ViewpointLockTracker._GetInstance