def on_cancel

      doc = fetch(fei)

      return unless doc

      r = @context.storage.delete(doc)

      on_cancel(fei, flavour) if r != nil
    end
def on_cancel

      doc = fetch(fei)

      return unless doc

      r = @context.storage.delete(doc)

      on_cancel(fei, flavour) if r != nil
    end
Removes the document/workitem from the storage.

 Warning: this method is called by the engine (worker), i.e. not by you.