code: @Override
  	public Element execute(Context context) {
  		Element result = Undef.VALUE;
  		for (Operation op : ops) {
  			try {
  				result = op.execute(context);
  			} catch (EvaluationException ee) {
  				throw ee.addExceptionInfo(sourceRange, context);
  			}
  		}
  		return result;
  	}
docs: Execution of a DML block consists simply of executing the block's
  arguments in order. If no arguments are run, then the value of the block
  is <code>Undef</code>.