Error "parent_children has no attrs name next"

[FabioColognesi]

Hello,
Trying to print a document having a lot of lines you got an error "parent_children has no attrs name next"
We are running aeroolib on debian10 under python 3.7

I changed file plugins/opendocument as attached and it works. It seems no portings were made on those usages because "parent_children" represents an iterator object having no need to call .next method.
opendocument.py.gz