======================================
DLL_NODE (invariant admissibility)
Successfully verified.
======================================
DLL_NODE.make (creator)
Successfully verified.
======================================
DLL_NODE.insert_right
Successfully verified.
======================================
DLL_NODE.remove
Successfully verified.
======================================
DLL_NODE.set_left
Successfully verified.
======================================
DLL_NODE.set_right
Successfully verified.
======================================
DLL_NODE.not_left
Successfully verified.
======================================
DLL_NODE.not_right
Successfully verified.