def perimeter():
n = 5nL = [1,1,]if n == 0: return 0if n == 1: return 1 * 4if n == 2: return 2 * 4rl = [nL.append(nL[i]+nL[i-1]) for i in range(1, n)]#这里rl为[None,None,None,None]但是nL为[1,1,3,5,8]print(rl)return 0