code: function noctua_edge(subject, object, predicate){
      bbop_edge.call(this, subject, object, predicate);
      this._is_a = 'bbop-graph-noctua.edge';
  
      // Edges are not completely anonymous in this world.
      this._id = bbop.uuid();
      this._predicate_label = null;
  
      this._annotations = [];
      this._referenced_subgraphs = [];
  }
docs: Sublcass of bbop-graph.edge for use with Noctua ideas and concepts.
  
  @constructor
  @see module:bbop-graph
  @alias edge
  @param {String} subject - required subject id
  @param {String} object - required object id
  @param {String} [predicate] - preidcate id; if not provided, will use defined default (you probably want to provide one--explicit is better)
  @returns {this}