def __init__(self, xfrom, xto, tagname, xmlns=None, content=None, **attr):
Element.__init__(self, tagname, xmlns, content, **attr)
self._routing = ''
if xfrom:
self._routing += ' from=%s' % xml.sax.saxutils.quoteattr(xfrom)
if xto:
self._routing += ' to=%s' % xml.sax.saxutils.quoteattr(xto)
