code: public static BitemporalMapper bitemporalMapper(String vtFrom, String vtTo, String ttFrom, String ttTo) {
          return new BitemporalMapper(vtFrom, vtTo, ttFrom, ttTo);
      }
docs: Returns a new {@link BitemporalMapper}.
  
  @param vtFrom the column name containing the valid time start
  @param vtTo the column name containing the valid time stop
  @param ttFrom the column name containing the transaction time start
  @param ttTo the column name containing the transaction time stop
  @return a new {@link BitemporalMapper}