in the story “sonnett” the author is trying to say when you are feeling down try to focus on something else than what is bugging you and try to be happy and not feeling blue in the sentence ‘’but do not let thy strength and courage fail’’ he is saying do not give up on something you try at you keep going just like Po when master Shifu tried to get rid of him but he did not leave he did not give up he kept going and beat Tylung so do not think you can’t think you can and a another sentence of the story is “my heart be brave and do not falter”he is saying to not get scared in a moment of terror
