After reading from an existing file with \'ugly\' XML and doing some modifications, pretty printing doesn\'t work. I\'ve tried etree.write(FILE_NAME, pretty_print=True
Here is an answer that is fixed to work with Python 3:
from lxml import etree
from sys import stdout
from io import BytesIO
parser = etree.XMLParser(remove_blank_text = True)
file_obj = BytesIO(text)
tree = etree.parse(file_obj, parser)
tree.write(stdout.buffer, pretty_print = True)
where text is the xml code as a sequence of bytes.