function getLodLerp(node, targetSse, levelBlendFactor) {
  if (node.parent === undefined) {
    return 0.0;
  }
  const sse = node.screenSpaceError;
  const parentSse = node.parent.screenSpaceError;
  const lodLerp = (targetSse - sse) / (parentSse - sse);
  const blended = (lodLerp + levelBlendFactor - 1.0) / levelBlendFactor;

  return CesiumMath.clamp(blended, 0.0, 1.0);
}
Compute an interpolation factor between a node and its parent
@param {SpatialNode} node
@param {number} targetSse
@param {number} levelBlendFactor
@returns {number}
@private