code: public static JComboBox leftShift(JComboBox self, Object i) {
          self.addItem(i);
          return self;
      }
docs: Overloads the left shift operator to provide an easy way to add
  items to a JComboBox.
  
  @param self a JComboBox
  @param i    an item to be added to the comboBox.
  @return same comboBox, after the value was added to it.
  @since 1.6.4