Hi all, coming back to what I proposed a while ago, we currently have this: class XMLParser: def __init__(self, **options): self.options = options class HTMLParser: ... doc = ET.parse(source, parser=XMLParser(configuration)) At the time, I brought up an equivalent for output formatting: class XMLFormatter: ... That would give us a nice, symmetric API for input and output options. And it allows you to use sublasses to provide different formats: class XMLPrettyPrinter(XMLFormatter): def __init__(self): self._pretty_print = True class XHTMLFormatter(XMLFormatter): def __init__(self): self._xhtml = True xml = ET.tostring(element, formatter=XMLPrettyPrinter()) ET.parse("myfile.xhtml").write("out.xhtml", formatter=XHTMLFormatter()) After Noah's latest approach in that direction, I think we should adopt this API for 1.0. A version 1.0 is supposed to provide a stable and somewhat future-proof API, and adding keyword arguments to various API functions all the time is not quite what I call future-proof. One reason is that you can't test for the availability of keyword arguments, so adding features at that level is difficult to handle for code that wants to support them as an option. So, I propose to replace the current pretty_print keyword (which only appeared in the beta version anyway) with a new XMLPrettyPrinter class and to provide new features preferably at a subclass level of XMLFormatter (e.g. XHTMLFormatter, etc.). An alternative name would be XMLSerializer, maybe that's more general. We could also leave the pretty_print keyword in as a shortcut, but that would obviously make things a bit more complicated internally. Maybe pretty printing will just become a general keyword of the XMLFormatter class, I guess that would make sense. I will have to check how to make these classes nicely usable internally, but that's a minor problem. We already use a lot of xmlBuffer code, so that should give us a common ground for this API. If there are no objections, I'll start getting my hands on this next week, so if anyone has an opinion on this, please speak up soon. Stefan