code: func isLastDimension(dimension, lastDimension uint64) bool {
  	if dimension >= lastDimension { // useful in testing and denotes a serious problem
  		panic(`Dimension is greater than possible dimensions.`)
  	}
  
  	return dimension == lastDimension-1
  }
docs: // isLastDimension simply returns dimension == lastDimension-1.
  // This panics if dimension >= lastDimension.