Sqlalchemy sqlite url relative to home or environment variable

A relative sqlalchemy path to a sqlite database can be written as:

sqlite:///folder/db_file.db

And an absolute one as:

sqlite:////home/user/folder/db_file.db

Is it possible to write a path relative to home? Like this:

sqlite:///~/folder/db_file.db

Or even better, can the path contain environment variables?

sqlite:////${MY_FOLDER}/db_file.db

This is the context of an alembic.ini file. So if the previous objectives are not possible directly, may I be able to cheat using variable substitution?

[alembic]
script_location = db_versions
sqlalchemy.url = sqlite:///%(MY_FOLDER)s.db
...