实现售汇操作：人民币→外币

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(____)
    cny_amount = ____
    annual_quota = ____
    used_quota = ____
    rate = conn.execute(____).fetchone()[____]
    usd_needed = round(____)
    remaining_quota = annual_quota - used_quota
    if usd_needed > remaining_quota:
        print(____)
    else:
        print({'____': cny_amount, '____': rate, '____': usd_needed, '____': round(____), '____': '____'})
    conn.close()