A new complete construction method for the system K

The proof of the completeness theorem for modal logic is a difficult and interesting thing. We generally prove this theorem with the canonical model method. Is there other proof method? So in this paper, we give another proof of the completeness theorem with respect to the class of all general frames. The set of possible worlds, W, is a set of all assignments. We construct an accessible relation over W, and give the detailed proof for the completeness theorem of the system K.