docs: def ReadPostingLists(self,
                         keywords,
                         start_time=FIRST_TIMESTAMP,
                         end_time=LAST_TIMESTAMP,
                         last_seen_map=None):
      """Finds all objects associated with any of the keywords.
  
      Args:
        keywords: A collection of keywords that we are interested in.
        start_time: Only considers keywords added at or after this point in time.
        end_time: Only considers keywords at or before this point in time.
        last_seen_map: If present, is treated as a dict and populated to map pairs
          (keyword, name) to the timestamp of the latest connection found.
      Returns:
        A dict mapping each keyword to a set of relevant names.
  
      """
      return data_store.DB.IndexReadPostingLists(
          self.urn, keywords, start_time, end_time, last_seen_map=last_seen_map)