查询各日期的汇率变动趋势

def solve():
    from pyodide.http import open_url
    offices_csv = open_url("https://data.zuihe.com/dbd/core/state_10/offices.csv").read()
    staff_csv = open_url("https://data.zuihe.com/dbd/core/state_10/staff.csv").read()
    currencies_csv = open_url("https://data.zuihe.com/dbd/core/state_10/currencies.csv").read()
    savings_products_csv = open_url("https://data.zuihe.com/dbd/core/state_10/savings_products.csv").read()
    clients_csv = open_url("https://data.zuihe.com/dbd/core/state_10/clients.csv").read()
    savings_accounts_csv = open_url("https://data.zuihe.com/dbd/core/state_10/savings_accounts.csv").read()
    savings_account_transactions_csv = open_url("https://data.zuihe.com/dbd/core/state_10/savings_account_transactions.csv").read()
    gl_accounts_csv = open_url("https://data.zuihe.com/dbd/core/state_10/gl_accounts.csv").read()
    exchange_rates_csv = open_url("https://data.zuihe.com/dbd/core/state_10/exchange_rates.csv").read()
    import sqlite3, pandas as pd
    from io import StringIO
    conn = sqlite3.connect(':memory:')
    pd.read_csv(StringIO(exchange_rates_csv)).to_sql('exchange_rates', conn, index=False, if_exists='replace')
    df = pd.read_sql_query("SELECT rate_date, rate FROM exchange_rates WHERE from_currency='USD' ORDER BY rate_date", conn)
    df['rate_change'] = df['rate'].diff().round(4)
    print(df.to_string(index=False))
    conn.close()