python上色,如何使用matplotlib生成着色区域

我试图在这个paper中得到图5，但我无法生成两个阴影区域，它们指示1和2 kcal/mol的误差。每个阴影区域必须与纸张中的颜色不同。我怎么能做到呢？在

#!/usr/bin/python

import numpy as np

import pylab as plot

import matplotlib.pyplot as plt

import numpy, scipy, pylab, random

from matplotlib.ticker import MultipleLocator

import matplotlib as mpl

from matplotlib.ticker import MaxNLocator

color = "#252525"

gray = "#777777"

with open("input.txt", "r") as f:

x=[]

y=[]

z=[]

for line in f:

if not line.strip() or line.startswith('@') or line.startswith('#'): continue

row = line.split()

x.append(float(row[0]))

y.append(float(row[1]))

z.append(float(row[2]))

fig = plt.figure(figsize=(3.2,2.2), dpi=300)

ax = plt.subplot(111)

plt.xlim(-2, -12)

plt.ylim(-2, -12)

ax.xaxis.set_major_locator(MaxNLocator(6))

ax.yaxis.set_major_locator(MaxNLocator(6))

ax.xaxis.set_minor_locator(MultipleLocator(1))

ax.yaxis.set_minor_locator(MultipleLocator(1))

plt.plot(x,y,'o',color="black", ms=3, mec="black")

plt.plot(x,z, color='gray' , linestyle = "dashed", dashes=(2,2))

plt.xlabel('Experimental (kcal/mol)', fontsize=8)

plt.ylabel('Predicted (kcal/mol)', fontsize=8)

for axis in ['top','bottom','left','right']:

ax.spines[axis].set_linewidth(0.5)

plt.subplots_adjust(top=0.95)

plt.subplots_adjust(bottom=0.18)

plt.subplots_adjust(left=0.14)

plt.subplots_adjust(right=0.95)

plt.tick_params(axis='both', which='major', labelsize=7)

plt.tick_params(axis='both', which='minor', labelsize=0)

plt.savefig("output.png", dpi=300)

输入文件：

^{pr2}$

获得的输出：