绘制房价波动图

import pandas as pd
import matplotlib
matplotlib.use(____)
import matplotlib.pyplot as plt

def solve():
    url = '____'
    df = pd.read_excel(____)
    plt.figure(figsize=(____, ____))
    plt.plot(____)
    plt.plot(____)
    plt.plot(____)
    plt.legend()
    plt.title(____)
    plt.tight_layout()
    plt.show()
    print(____)