Banking System (Progressive OOD)

Requirements Implement four progressively richer levels on one shared Bank class. Level 1 — Core account operations create_account(timestamp, account_id) -> bool — create the account only when the identifier is unused; otherwise return false. deposit(timestamp, account_id, amount) -> int None — add the amount and return the resulting balance, or return None when the account is unknown. transfer(timestamp, source, target, amount) -> int None — move funds and return the source…