实现外币折算人民币（按当日汇率）

def solve():
    from pyodide.http import open_url
    offices_csv = open_url(____).read()
    staff_csv = open_url(____).read()
    currencies_csv = open_url(____).read()
    savings_products_csv = open_url(____).read()
    clients_csv = open_url(____).read()
    savings_accounts_csv = open_url(____).read()
    savings_account_transactions_csv = open_url(____).read()
    gl_accounts_csv = open_url(____).read()
    exchange_rates_csv = open_url(____).read()
    import sqlite3, pandas as pd
    from io import StringIO
    conn = sqlite3.connect(____)
    pd.read_csv(StringIO(____)).to_sql(____)
    transactions = [(____),(____),(____)]
    rates = {r[____]:r[____] for r in conn.execute(____).fetchall()}
    print(____)
    for cur, amt in transactions:
        rate = rates.get(____)
        cny = round(____)
        print(____)
    conn.close()