+
+ validates :user, :presence => true, :associated => true
+ validates :k, :v, :length => 1..255, :characters => true
+
+ # Turn this Node in to an XML Node without the <osm> wrapper.
+ def to_xml_node
+ el1 = XML::Node.new "preference"
+ el1["k"] = k
+ el1["v"] = v
+
+ el1
+ end