docs: function addBlock(that, id, type, positions, type2) {
          var block, options;
          options = {};
  
          options.id = id || J.uniqueKey(that.blocksIds, type);
          options.type = type;
          options.positions = positions;
  
          that.currentBlockType = type2;
  
          // Create the new block, and add it block arrays.
          block = new node.Block(options);
          that.unfinishedBlocks.push(block);
          that.blocks.push(block);
  
          // Save block id into the blocks map.
          that.blocksIds[options.id] = (that.blocks.length - 1);
      }