code: func (p Pages) Reverse() Pages {
  	const key = "pageSort.Reverse"
  
  	reverseFunc := func(pages Pages) {
  		for i, j := 0, len(pages)-1; i < j; i, j = i+1, j-1 {
  			pages[i], pages[j] = pages[j], pages[i]
  		}
  	}
  
  	pages, _ := spc.get(key, reverseFunc, p)
  
  	return pages
  }
docs: // Reverse reverses the order in Pages and returns a copy.
  //
  // Adjacent invocations on the same receiver will return a cached result.
  //
  // This may safely be executed  in parallel.