### What does from `sage.all import *` do?

This question is relatd with another one: What packages in sage can I use in python?(ask.sagemath.org/question/35464/what-packages-in-sage-can-i-use-in-python/)

How do I import Sage into a Python script (doc.sagemath.org/html/en/faq/faq-usage.html#how-do-i-import-sage-into-a-python-script) told me that to use from `sage.all import *`

to import sage packages in python. When I list the installed sage packages, there is igraph and python-igraph. But from sage.all import * will not import them into python. I'd like to know, what kind of packages can be imported when I use `from sage.all import *`

.

BTW, the proper way to use `igraph`

in python is `import igraph`

with `python_igraph`

installed.

ps: My karma is insufficient to publish links.