'Send an XML object on the stream, and optionally wait
for a response.
:param data: The :class:`~xml.etree.ElementTree.Element` XML object
to send on the stream.
:param mask: **DEPRECATED**
An XML string snippet matching the structure
of the expected response. Execution will block
in this thread until the response is received
or a timeout occurs.
:param int timeout: Time in seconds to wait for a response before
continuing. Defaults to :attr:`response_timeout`.
:param bool now: Indicates if the send queue should be skipped,
sending the stanza immediately. Useful mainly
for stream initialization stanzas.
Defaults to ``False``.'

def send_xml(self, data, mask=None, timeout=None, now=False):

    if (timeout is None):
        timeout = self.response_timeout
    return self.send(tostring(data), mask, timeout, now)
