code: @JsonIgnore
      @SuppressWarnings("unchecked")
      public List<HalRepresentation> getItemsBy(final String rel) {
          if (!hasItem(rel)) {
              return emptyList();
          } else {
              final Object item = items.get(curies.resolve(rel));
              return item instanceof List
                      ? (List<HalRepresentation>) item
                      : singletonList((HalRepresentation) item);
          }
      }
docs: Returns the embedded items by link-relation type.
  <p>
  If no items with this type are embedded, an empty list is returned.
  
  @param rel the link-relation type
  @return list of embedded HAL representations for the link-relation type
  
  @since 0.1.0