code: public DataType<Boolean> getType(String grp, Number idx, boolean ml, boolean mv, boolean req, String... params) {
          return new BooleanAttribute(grp, idx, ml, mv, req);
      }
docs: Technically, you can have a multi-lingual or multi-valued boolean, but why would you?
  @param ml true if the boolean is multi-lingual
  @param mv true if the boolean can support multiple values
  @param req true if the boolean is required
  @param params unused
  @return a boolean instance