When use IDLE to open a file and start a new IDLE windows from "Python Shell" button, you can import the modules that are the child modules in the module "idlelib", such as "help", "pyshell". Think for that there are many schools still use IDLE to teach python to prevent the students to install malicious plugins from other IDE, if the students try to import these modules, it will result in misleading.

import help

This code is wrong in cmd and any other IDE but "normal" in IDLE, and what is imported is "idlelib.help".