code: function implicit_views(g, options) {
      var default_view = options.default_view || 'table';
  
      var leaves = g.get_leaves();
      var table;
      _.each(leaves, function(node) {
          if (!is_sink(node)) {
              table = g.add_node('View', default_view);
              g.add_edge(node, table);
          }
      });
  }
docs: Generate a graph builder that adds an implicit sink of the given type to any branches of the graph that don't already end in a sink.