/**
     * Returns the dependency type id.
     * The id uniquely identifies this <i>dependency type</i>.
     *
     * @return the id of this type, never {@code null}.
     */
    @Nonnull
    String id();

    /**
     * Returns the dependency type language.
     *
     * @return the language of this type, never {@code null}.
     */
    @Nonnull
    Language getLanguage();

    /**