Shelve has inconsistent file naming, causing weirdness sometimes when you try to use it.

safe_shelve.py

"""safe_shelve.py"""
import os
import shelve

DATA_DIR = 'data'


def open(db_name: str):
    """Opens and returns a shelve in an unambiguous place."""
    directory = os.path.join(DATA_DIR, db_name)
    db = os.path.join(directory, db_name)
    os.makedirs(directory, exist_ok=True)
    return shelve.open(db)


def list(db_name):
    """List available shelves."""
    return os.listdir(DATA_DIR)