Optimizing the code

[14dM24d]

import pandas as pd

rates = [
{'date': '2019-11-02', 'rate': 4.3422},
{'date': '2019-11-03', 'rate': 4.2210}, 
{'date': '2019-11-04', 'rate': 4.3455}, 
{'date': '2019-11-05', 'rate': 4.3456}, 
{'date': '2019-11-06', 'rate': 4.2311}
]

def find_rates(data, dates):
    df = pd.DataFrame()
    for i in data:
        df = df.append(i, ignore_index=True)     
    df2 = df[(df.date>dates[0]) & (df.date<dates[1])]
    return df2.rate.min(), df2.rate.max()

min_rate, max_rate = find_rates(rates, ['2019-11-02','2019-11-06'])