code: <A> AttributeSet withInternal(
          AttributeKey<A> key,
          A value
      ) {
  
          Map<String, Object> map = new HashMap<>(this.internals);
          if (value == null) {
              map.remove(key.name());
          } else {
              map.put(key.name(), value);
          }
          return new AttributeSet(this.attributes, this.locale, this.level, this.section, this.printCondition, map);
  
      }
docs: <p>Setzt das angegebene interne Attribut neu. </p>
  
  @param   <A> generic type of attribute value
  @param   key     attribute key
  @param   value   attribute value (if {@code null} then the attribute will be removed else inserted or updated)
  @return  changed attribute set
  @since   3.11/4.8