def load_trackers
      tracker_hits_per_path_hashes = tracker_files.map do |full_path|
        JSON.parse(full_path.binread).transform_keys(&:to_sym).yield_self do |version:, tracker_hits_per_path:|
          raise "dump version mismatch: #{version}, currently #{VERSION}" unless version == VERSION
          tracker_hits_per_path
        end
      end

      self.class.merge_tracker_hits_per_paths(*tracker_hits_per_path_hashes)
    end
def load_trackers
      tracker_hits_per_path_hashes = tracker_files.map do |full_path|
        JSON.parse(full_path.binread).transform_keys(&:to_sym).yield_self do |version:, tracker_hits_per_path:|
          raise "dump version mismatch: #{version}, currently #{VERSION}" unless version == VERSION
          tracker_hits_per_path
        end
      end

      self.class.merge_tracker_hits_per_paths(*tracker_hits_per_path_hashes)
    end
returns a TrackerHitsPerPath