Best/your practices in Python for sharing global variables, shared functions and classes

Best/your practices in Python for sharing global variables, shared
functions and classes

Thanks for looking at this, I've been mulling over this for hours to no
avail. Essentially, I want to make my code more modular and share-able:
you can see how the following files made up a much larger one initially.
It's not working and I suspect it's because I'm trying to do things in
Python that I'm not supposed to:
app_config.py
app_name = "quick scraper"
mysql_db = ... # intended "global" variable that connects to database
main.py
from app_config import * # Getting shared variables
import app_library # See code app_library.py below
...
logger = logging.getLogger(app_name) # logger object to be shared later
...
app_library.dlAndSaveWebpage(url) # Module has key helper functions
...
app_library.py
import app_models_orm as app_models
def dlAndSaveWebpage(url)
# download and process url
...
app_models.Webpage(url=url, body=body)
app_models_orm.py
class MySQLModel(Model):
class Meta:
database = mysql_db
class Webpage(MySQLModel):
id = ...
...
Class MySQLModel of app_models_orm.py fails because variable mysql_db does
not exist in the file. I could do an import app_config, but I want to have
app_models_orm.py be used by multiple scripts within the same directory.
If I have to do an import of a file custom to a script, then I'd have to
make copies of the models file, which just seems bizarre and wrong.
Similarly, I want to use app_library.py by multiple scripts in the same
directory. It seems to make sense to call app_library from main.py, but if
app_library needs to reference variables directly from app_config.py, I'd
have to also make copies of app_library.py.
main.py contains a logger object that, when all of this code was put
together in one file, all the various methods could access/use. How can
(or should?) app_library.py functions access this instance of the logger
class?
Again, thanks for the help. Feel free to "teach me how to catch fish" in
this instance too: I saw many posts about using a global import file, but
that doesn't help the intention to share the latter two files without
adding in custom imports, nor does it help with the models file which,
when imported, hits an error because the class is seeking a variable that
isn't in the file. There's probably a right way to do all this, and I
imagine many of you would know how.