human
I wrote the below code

    if (doctype is not None):
        request.write(doctype)
        request.write('\n')
    if (_failElement is None):
        _failElement = twisted.web.util.FailureElement
    d = flatten(request, element, request.write)
    def eb(failure):
        log.err(failure, 'An    error    occurred    while    rendering    the    response.')
        if request.site.displayTracebacks:
            return flatten(request, _failElement(failure), request.write).encode('utf8')
        else:
            request.write('<div    style="font-size:800%;background-color:#FFF;color:#F00">An    error    occurred    while    rendering    the    response.</div>')
    d.addErrback(eb)
    d.addBoth((lambda _: request.finish()))
    return NOT_DONE_YET

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def renderElement(request, element, doctype='<!DOCTYPE    html>', _failElement=None):