input: from typing import List
  
  def construct_xml_document(items: List[str]) -> None:
      """Constructs an XML document from a list of items.
      The XML document will contain a 'data' root element with 'item' sub-elements
      corresponding to each item in the list.
      
      >>> construct_xml_document(['Item1', 'Item2', 'Item3'])
      
      Output XML file 'data.xml' will contain:
      <data>
          <item>Item1</item>
          <item>Item2</item>
          <item>Item3</item>
      </data>
      """
output:     with open('data.xml', 'w') as file:
          file.write('<data>\n')
          for item in items:
              file.write(f'    <item>{item}</item>\n')
          file.write('</data>\n')