1、首先进入python shell界面，不会的话看我前面的经验吧。
2、输入help，弹出了提示：Type help() for interactive help, or help(object) for help about object.需要交互式的帮助的话输入help（）；需要查看某个对象的帮助的话用help（对象）。
3、我们进入交互式帮助界面。help（）
4、进入交互式帮助界面，命令提示变成了这样。
Welcome to Python 3.6's help utility!
If this is your first time using Python, you should definitely check out
the tutorial on the Internet at https://docs.python.org/3.6/tutorial/.
Enter the name of any module, keyword, or topic to get help on writing
Python programs and using Python modules. To quit this help utility and
return to the interpreter, just type "quit".
To get a list of available modules, keywords, symbols, or topics, type
"modules", "keywords", "symbols", or "topics". Each module also comes
with a one-line summary of what it does; to list the modules whose name
or summary contain a given string such as "spam", type "modules spam".
5、如果我想获取input函数的功能，输入input就可以了
Help on built-in function input in module builtins:
input(prompt=None, /)
Read a string from standard input. The trailing newline is stripped.
The prompt string, if given, is printed to standard output without a
trailing newline before reading input.
If the user hits EOF (*nix: Ctrl-D, Windows: Ctrl-Z+Return), raise EOFError.
On *nix systems, readline is used if available.
6、这个功能将在学习中起到很大的帮助，不过需要看得懂英语。那么怎么退出帮助命令行呢？输入quit就可以了。
You are now leaving help and returning to the Python interpreter.
If you want to ask for help on a particular object directly from the
interpreter, you can type "help(object)". Executing "help('string')"
has the same effect as typing a particular string at the help> prompt.
