The Searcher.search_page() function is not documented except that ResultsPage documentation points to it.
The code in the ResultsPage documentation calls a non-existent find_page function.
It is also worthwhile pointing out that searching for a particular page is not "efficient". ie if you ask for page 100 the search actually has to find pages 1 through 99 to give you page 100. It would be nice if search took an offset parameter so that it knew the first N results are being ignored. That could help with optimizations in the future.