docs: public CEDescrBuilder<CEDescrBuilder<P, T>, NotDescr> not() {
          CEDescrBuilder<CEDescrBuilder<P, T>, NotDescr> not = new CEDescrBuilderImpl<CEDescrBuilder<P, T>, NotDescr>( this, new NotDescr() );
          ((ConditionalElementDescr) descr).addDescr( not.getDescr() );
          return not;
      }