input: Write a function to create an XML document using Python which contains a list of items provided as input. The function should return the XML tree.
  
  
  assert create_xml(['Item1', 'Item2', 'Item3'])
  # Expected XML content:
  # <data>
  #     <item>Item1</item>
  #     <item>Item2</item>
  #     <item>Item3</item>
  # </data>
  assert create_xml(['Apple', 'Banana', 'Cherry'])
  # Expected XML content:
  # <data>
  #     <item>Apple</item>
  #     <item>Banana</item>
  #     <item>Cherry</item>
  # </data>
  assert create_xml([])
  # Expected XML content:
  # <data/>
  
output: from xml.etree.ElementTree import Element, SubElement, tostring
  
  def create_xml(items):
      root = Element('data')
      for item in items:
          item_elem = SubElement(root, 'item')
          item_elem.text = item
      return root