Two built-in modules in Python introduce _python

After using Python for a while, it can be said that the basic unit of Python is the module, and we use the import statement to import it when we use the module, but we can use some of these functions when we're not importing any modules: Int (), str (), Len (), Range (), and use a try except statement to catch exceptions, and where do these come from?

Basic

Python automatically imports the built-in __builtin__ and exceptions two modules at startup so that any program can use them, so these two modules should be the most important modules in the entire Python language.

Extended

Something about the implementation of these two modules:
__builtin__
Exceptions