code: public Checkbox setChecked(boolean checked) {
          if (checked) {
              String valueEnabledString = this.getEnabledValueString();
              this.setValue(valueEnabledString);
          } else {
              this.setValue("");
          }
  
          return this;
      }
docs: Checks or unchecks this checkbox element.
  
  @param checked True for checked, false for not checked
  @return This element