input: Write a function to construct an XML document using Python which contains the provided list of items. The function should take a list of strings as input and generate an XML file named 'data.xml'. The root element should be 'data', and each item in the list should be a sub-element of the root with the tag 'item'.
  assert construct_xml(['Item1', 'Item2', 'Item3'])==None
  assert construct_xml(['ItemA', 'ItemB'])==None
  assert construct_xml(['Apple', 'Banana', 'Cherry'])==None
  assert construct_xml([])==None
output: def construct_xml(items):
      from xml.etree.ElementTree import Element, SubElement, tostring
      root = Element('data')
      for item in items:
          SubElement(root, 'item').text = item
      with open('data.xml', 'wb') as f:
          f.write(tostring(root))