在python中修改matplolib图例

我目前使用以下代码绘制数据：

#
#Plotting
plt.plot(temp1, densityHEX,'bo',markersize='12',label='Hexadecane MD')
plt.plot(expTempHexa,expDensHexa,'bo',markersize='12',markerfacecolor='none',label='Hexadecane Exp')

plt.plot(temp2, densityLAU,'rs',markersize='12',label='Methyl Laurate MD')
plt.plot(expTempLau2,expDensLau2,'rs',markersize='12',markerfacecolor='none',label='Methyl Laurate Exp')

plt.plot(temp2, densityMIX,'^',color='indigo',markersize='12',label='Mixture 1:1 MD')
plt.plot(expTempMix,expDensMix,'^',color='indigo',markersize='12',markerfacecolor='none',label='Mixture 1:1 Exp')

leg = plt.legend(loc='best',ncol=2,frameon=False,prop={'size': 13})
leg.get_frame().set_edgecolor('k')
plt.ylabel(r'$\rho$ (g/cm$^3$)',fontsize = 22)
plt.xlabel('T (K)',fontsize = 22)
plt.ylim((0.650,1.0))
plt.tight_layout()
plt.savefig("rhoCombined3.pdf", format='pdf')

输出如下：

我想知道是否有办法修改图例以获得类似的内容：

一个选项是：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.legend_handler import HandlerTuple

x = np.arange(10)
y = x*0.2

#Plotting
l1, = plt.plot(x,y+0.0, 'bo', markersize='12', label='Hexadecane MD')
l2, = plt.plot(x,y+0.3, 'bo', markersize='12', markerfacecolor='none', label='Hexadecane Exp')

l3, = plt.plot(x,y+1.0, 'rs', markersize='12', label='Methyl Laurate MD')
l4, = plt.plot(x,y+1.3, 'rs', markersize='12', markerfacecolor='none', label='Methyl Laurate Exp')

l5, = plt.plot(x,y+2.0, '^', color='indigo', markersize='12', label='Mixture 1:1 MD')
l6, = plt.plot(x,y+2.3, '^', color='indigo', markersize='12', markerfacecolor='none',label='Mixture 1:1 Exp')

plt.legend(handles=[(l1, l2), (l3, l4), (l5, l6)], 
           labels=["Hexadecane", "Methyl Laurate", "Mixture 1:1"],
           handler_map={tuple: HandlerTuple(ndivide=2)}, 
           handlelength=3,
           title="MD  Exp                         ")
plt.show()

将标题误用为“列标题”是一种肮脏的攻击。但它很快就会给出所需的输出

您可以“滚动您自己的”图例，但据我所知，matplotlib开箱即用不支持这种类型的布局。