object handl handl order kind handl replac ok handl concurr kind handl replac cck handl changeabl kind handl replac ck handl visibl kind handl replac vk handl aggreg kind handl replac ak handl paramet direct kind handl replac pdk handl model element model element model element handl handl multipl model impl data type helper multipl handl handl express express handl bodi handl element resid handl templat paramet todo want construct artifici buffer result buffer model element templat templat paramet handl templat templat templat result append result append model element paramet templat paramet handl paramet paramet paramet result append todo non model element type need handl invalid object except uuid uuid handl uuid invalid element except uuid uuid invalid element except illeg argument except mdr element suppli receiv handl 