str对象,统一的Unicode字符串

../../_images/242d7e5b9acacc811cdd0cfeda58b853.png
../../_images/c7ed1f2813f3de6c0b515bc9d47fe35f.png
../../_images/dd7122b033c3382ad9216a9dd0c96586.png
../../_images/2ee1ff0071620957445deadae78f7178.png
../../_images/c83c7fc05a32dd9f79cfb6bda82d29c7.png
../../_images/23de575d85e89e454d1eae82a189050e.png