code: @SuppressWarnings("unchecked")
      public Object getFirstKeyPart() {
          Object keyPart = null;
          if (this.key.value() instanceof List && !((List<Object>) this.key.value()).isEmpty()) {
              keyPart = ((List<Object>) this.key.value()).get(0);
          } else {
              // UniqueKey or MultitontKey with only one key part
              keyPart = this.key.value();
          }
          return keyPart;
      }
docs: Return the first key part of the {@link MultitonKey} or the component class type for {@link UniqueKey}.
  
  @return Returns the first key part or the component type.