code: function(containerBlock) {
      var clauseBlock = containerBlock.nextConnection.targetBlock();
      var i = 1;
      while (clauseBlock) {
        switch (clauseBlock.type) {
          case 'controls_if_elseif':
            var inputIf = this.getInput('IF' + i);
            var inputDo = this.getInput('DO' + i);
            clauseBlock.valueConnection_ =
                inputIf && inputIf.connection.targetConnection;
            clauseBlock.statementConnection_ =
                inputDo && inputDo.connection.targetConnection;
            i++;
            break;
          case 'controls_if_else':
            var inputDo = this.getInput('ELSE');
            clauseBlock.statementConnection_ =
                inputDo && inputDo.connection.targetConnection;
            break;
          default:
            throw 'Unknown block type.';
        }
        clauseBlock = clauseBlock.nextConnection &&
            clauseBlock.nextConnection.targetBlock();
      }
    }
docs: Store pointers to any connected child blocks.
  @param {!Blockly.Block} containerBlock Root block in mutator.
  @this Blockly.Block