 [det]xmld_signed_DOM(+DOM, 
-SignedDOM, +Options)
[det]xmld_signed_DOM(+DOM, 
-SignedDOM, +Options)
The SignedDOM must be emitted using xml_write/3 
or
xml_write_canonical/3. If xml_write/3 
is used, the option
layout(false) is needed to avoid changing the layout of the
SignedInfo element and the signed DOM, which 
will cause the signature to be invalid.