'Get this batch as XML'

def to_xml(self):

    assert (self.connection is not None)
    s = '<?xml    version="1.0"    encoding="UTF-8"?>\n'
    s += ('<InvalidationBatch    xmlns="http://cloudfront.amazonaws.com/doc/%s/">\n' % self.connection.Version)
    for p in self.paths:
        s += ('                <Path>%s</Path>\n' % self.escape(p))
    s += ('                <CallerReference>%s</CallerReference>\n' % self.caller_reference)
    s += '</InvalidationBatch>\n'
    return s
