ATM Simulator CLI with Card Auth

import sqlite3

def init_bank_db():
    with sqlite3.connect("bank.db") as conn:
        cursor = conn.cursor()
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS accounts (
                account_num TEXT PRIMARY KEY,
                pin_hash TEXT NOT NULL,
                balance REAL NOT NULL CHECK(balance >= 0)
            )
        """)
        cursor.execute("""
            CREATE TABLE IF NOT EXISTS ledger (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                account_num TEXT NOT NULL,
                type TEXT CHECK(type IN ('DEPOSIT', 'WITHDRAWAL')),
                amount REAL NOT NULL,
                timestamp TEXT NOT NULL,
                FOREIGN KEY(account_num) REFERENCES accounts(account_num)
            )
        """)
        conn.commit()