ElementTree write function does not write to standard out

Question

I'm trying to output an XML structure to stdout with ElementTree. I'm trying with:

root = ET.Element('networkData')    
tree = ET.ElementTree(root)
tree.write(sys.stdout)

but I get no output. Changing the argument to a string produces an XML file as expected. Using the debugger (adding encoding tip from SO) I get:

-> tree.write(sys.stdout, encoding='utf-8')
(Pdb) n
TypeError: write() argument must be str, not bytes

Googling the error I get a few hits but none that seems to address this issue. Also, I get confused by the error message as sys.stdout is a _io.TextIOWrapper object.

Answer 1

The problem has to do with encoding. Without correct encoding, the argument is treated as binary and not as string, which explains the error message. The proper write-statement should be:

tree.write(sys.stdout, encoding='unicode')

or

tree.write(sys.stdout.buffer)

as pointed out in the comments.