li = [1,2,3,[1,2,['ab','cd'],'wang'],'wo']
w = li[3][2][1][0]
print(w)
————————
c

li = [1,2,3,[1,2,['ab','cd'],'wang'],'wo']

s = ''
for i in li:
    s += str(i)
print(s)
————————
123[1, 2, ['ab', 'cd'], 'wang']wo