code: def search_info(self, search_index):
          
          ddoc_search_info = self.r_session.get(
              '/'.join([self.document_url, '_search_info', search_index]))
          ddoc_search_info.raise_for_status()
          return response_to_json_dict(ddoc_search_info)
docs: Retrieves information about a specified search index within the design
          document, returns dictionary
  
          GET databasename/_design/{ddoc}/_search_info/{search_index}