Python Matplotlib中的曲线箭头样式

I am trying to replicate this:

我已经走得很远了:

import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
import numpy as np
import pandas as pd


colors = ["#CC5A43","#CC5A43","#2C324F"]

data = {
    "year": [2004, 2022, 2004, 2022, 2004, 2022],
    "countries" : [ "Denmark", "Denmark", "Norway", "Norway","Sweden", "Sweden",],
    "sites": [4,10,5,8,13,15]
}
df= pd.DataFrame(data)
df = df.sort_values(['countries' ,'year' ], ascending=True ).reset_index(drop=True)
df['ctry_code'] = df.countries.astype(str).str[:2].astype(str).str.upper()
df['year_lbl'] ="'"+df['year'].astype(str).str[-2:].astype(str)
df['sub_total'] = df.groupby('year')['sites'].transform('sum')
no_bars = df.sub_total.max()
sub_totals = df.sub_total.unique()
years= df.year.unique()
fig, axes = plt.subplots(nrows=2, ncols=1,figsize=(6, 6), subplot_kw=dict(polar=True))
fig.tight_layout(pad=3.0)

colors = [["#CC5A43"]*4 +["#2C324F"]*5 + ["#5375D4"]*13,
          ["#CC5A43"]*10 +["#2C324F"]*8 + ["#5375D4"]*15]

for sub_total, year,color,ax in zip( sub_totals, years,colors,axes.ravel()):
        angles =  np.arange(0,2*np.pi,2*np.pi/sub_total)
        ax.plot([angles, angles],[0,1],lw=4, c="#CC5A43")
        ax.set_rorigin(-4)
        ax.set_theta_zero_location("N")
        ax.set_yticklabels([])
        ax.set_xticklabels([])
        ax.grid(False)
        ax.spines[['polar','inner']].set_color('w')
        ax.text(np.pi/2,-3.2, year,va="center" )
        for i, j in enumerate(ax.lines):
                j.set_color(color[i])

#add legend
color_legend = [ "#A54836", "#5375D4", "#2B314D",]
lines = [Line2D([0], [0], color=c, linestyle='-', lw=4,) for c in color_legend]
labels = df.countries.unique().tolist()
plt.legend(lines, labels,
           bbox_to_anchor=(1.5, -0.02), loc="lower center",
            frameon=False, fontsize= 10)

which produces:

但我真的在挠头，不知道如何做注解的"箭头":

我希望‘-(’能行得通，但它不行.

我的问题是，我需要为这个创建我自己的arrwostyle(这是一个好的参考资料吗？)，或者有没有更明显的方法来做，而我完全错过了它？