How Python invokes its own written package __python

As Little white has just touched the language of Python, Because you don't know how to import your own. py file has been plagued for a long time, and finally found a way to import the SYS package under the Python interface, and then put the module that you wrote into a folder, using Sys.path.append (' The exact location of the package ') You can then refer to the functions within the. py file, and I find that once the package is imported, you modify the code in the module, such as adding a function, the added function will not be found in the module