# modify an existing element. again, this code doesn't directly deal
# with types, but uses duck typing to handle them transparently.
with_model do |model, xml|
# get the new element from the XML payload
# modify an existing element. again, this code doesn't directly deal
# with types, but uses duck typing to handle them transparently.
with_model do |model, xml|
# get the new element from the XML payload