How to write XML declaration using xml.etree.ElementTree

Question

I am generating an XML document in Python using an ElementTree, but the tostring function doesn\'t include an XML declaration when converting to plaintext.

Answer 1

Another pretty simple option is to concatenate the desired header to the string of xml like this:

xml = (bytes('\n', encoding='utf-8') + ET.tostring(root))
xml = xml.decode('utf-8')
with open('invoice.xml', 'w+') as f:
    f.write(xml)