How to replace/remove prototype plugin dependency - messages

e_classifieds plugin doesn't work without prototype plugin, but only reason I was able to find was message functionality.  To remove php errors without any other changes in new version:

before:

$prototype_obj->message_box($eclassf_msgtype, $eclassf_msgtext)

after 

e107::getMessage()->add($eclassf_msgtext, $eclassf_msgtype)->render()

It's all for now.