Convenience method for adding an element with no children.

def addQuickElement(self, name, contents=None, attrs=None, escape=True, cdata=False):
        """Convenience method for adding an element with no children."""
        if attrs is None:
            attrs = {}
        self.startElement(name, attrs)
        if contents is not None:
            self.characters(contents, escape=escape, cdata=cdata)
        self.endElement(name)