To convert an Element and its content back
to XML, use a function call of this form:
etree.tostring ( elt, pretty_print=False )
where elt is an Element
instance. The function returns a string containing the
XML. For an example, see Section 6.8, “The SubElement() constructor”.
If you set the optional pretty_print
argument to True, the method will attempt
to insert line breaks to keep line lengths short where
possible.