Python - Modifying xml file erases comments [duplicate]

This question already has an answer here:

• How to prevent xml.ElementTree fromstring from dropping commentnode 1 answer

Let's say my xml file looks like this:

<Products>
  <Product name="first" />

  <!-- some comment -->
  <Product name="second" />

  <Product name="third" />
</Products>

And my script:

import xml.etree.ElementTree as ET

tree = ET.parse('test.xml')
root = tree.getroot()

elem = ET.Element('Product')
elem.attrib['name'] = 'fourth'

root.append(elem)

tree.write('test.xml')

The resulting xml will look like this:

<Products>
  <Product name="first" />

  <Product name="second" />

  <Product name="third" />
<Product name="fourth" /></Products>

First, the formatting is a little off (spaces and new lines), but the thing that bothers me is that the comment line in not in the new file.

Is there a way to modify a xml file without losing those?