使用 解包以在函数调用期间扩展数组.

Use unpacking to expand the array during the function call.

print(hex_string.format(*letters))

输出:

            _____
           /     \
          /       \
    ,----(    1    )----.
   /      \       /      \
  /   2    \_____/   3    \
  \        /     \        /
   \      /       \      /
    )----(    4    )----(
   /      \       /      \
  /        \_____/        \
  \   5    /     \   6    /
   \      /       \      /
    `----(    7    )----'
          \       /
           \_____/