code: public Packer setAnchorNorth(final boolean how) {
          if (how == true) {
              gc.anchor = GridBagConstraints.NORTH;
          } else {
              gc.anchor &= ~GridBagConstraints.NORTH;
          }
          setConstraints(comp, gc);
          return this;
      }
docs: Add anchor=NORTH to the constraints for the current component if how ==
  true remove it if false.