I have the following code that is intended to look at the “delta” values and where they are negative the relevant subplot background color should either become red or green:

def chartit():
    global strikes
    chartlist = []
    src = r'C:UsersUserPycharmProjectsactivetickhttp v3spyvalue.txt'
    dst = r'C:UsersUserPycharmProjectspythonProject6spyvalue.txt'
    shutil.copyfile(src, dst)
    file = open("spyvalue.txt", "r")
    spyprice = file.readline()
    spyprice = round(float(spyprice), 0)
    print("spy price is ", spyprice)
    upper = int(spyprice) + 3
    lower = int(spyprice) - 3
    for item in strikes:
        if float(item) <= upper and float(item) >= lower:
            chartlist.append(item)

    chartlist.sort()
    print("chart list is ", chartlist)
    count = 1
    apds = []
    resampled_data = {}
    for item in chartlist:
        file = open(str(item) + ".txt", "r")
        df = pd.read_csv(str(item) + ".txt")
        df['time'] = pd.to_datetime(df['time'])
        df = df.set_index('time')
        resampled = df['delta'].resample('s').ohlc()
        resampled_data[item] = resampled
        apds.append(mpf.make_addplot(resampled,type="candle",panel=count,ylabel=str(item)))
        count = count + 1

    fig, axlist = mpf.plot(resampled, addplot=apds,ylabel="SPY", returnfig=True)

    for i in range(1, len(axlist)):  # Start from 1 to skip the main plot
        if i-1 < len(chartlist):  # Ensure we don't exceed the chartlist length
            strike = chartlist[i-1]
            print(strike)
            set_background_color(axlist[i], resampled_data[strike]['close'])
    #for x in range(0,count):
    #    for strike in chartlist:
    #        set_background_color(axlist[count], resampled_data[strike]['close'])
    #formatter = FuncFormatter(custom_formatter)
    #for ax in axlist:
    #    ax.yaxis.set_major_formatter(formatter)
    mpf.show()

def set_background_color(ax, series):
    # Find the first non-NaN value in the series to set the initial color
    if series.dropna().iloc[0] >= 0:
        initial_color = 'lightgreen'
        print("green")
    else:
        initial_color = 'red'
        print("red")
    ax.set_facecolor(initial_color)

def custom_formatter(x, pos):
    formatted = f'{x:.1e}'
    # Replace 'e' with 'x10^' and ensure the exponent is only 1 digit if possible
    base, exponent = formatted.split('e')
    exponent = int(exponent)
    return f'{base}x10^{exponent}'

I want each -ve delta to be red in background and position to be green. But instead I get this: