Incorrect use of ParentDataWidget code example

Example: Incorrect use of ParentDataWidget

In this case just removing Expanded or wrapping it in a Column should fix the 
problem.

An Expanded widget must be a descendant of a Row, Column, or Flex

The fix for this above issue, is to move the expanded widget inside a flex 
widget. Example below.

Row(
    children: [
      Expanded(
        ... ... ..
        .... .. .. 
      ),
      ......
      ......
    ],
 ),