def METHOD_NAME(x_range, y_range):
    global df
    if df is None:
        xs = np.random.normal(loc=0, scale=500000, size=10000000)
        ys = np.random.normal(loc=0, scale=500000, size=10000000)
        df = pd.DataFrame(dict(x=xs, y=ys))
    return df.loc[df['x'].between(*x_range) & df['y'].between(*y_range)]