code: def namedb_get_history( cur, history_id, offset=None, count=None, reverse=False ):
      
      # get history in increasing order by block_id and then vtxindex
      history_rows = namedb_get_history_rows( cur, history_id, offset=offset, count=count, reverse=reverse )
      return namedb_history_extract( history_rows )
docs: Get all of the history for a name or namespace.
      Returns a dict keyed by block heights, paired to lists of changes (see namedb_history_extract)