mac上Python matplotlib中文显示问题

# -*- coding: UTF-8 -*-
import numpy as np

import matplotlib.pyplot as plt
from matplotlib.font_manager import FontProperties

x = np.linspace(0,2*np.pi,50)
plt.plot(x,np.sin(x),'r-x',label='Sin(x)')
plt.plot(x,np.cos(x),'g-',label='Cos(x)')
plt.legend()
#主要是下面
font = FontProperties(fname='/System/Library/Fonts/PingFang.ttc')
plt.xlabel(u'横', fontsize=18, fontproperties=font)
plt.ylabel(u'纵', fontsize=18, fontproperties=font)
plt.title(u'秦时明月', fontsize=18, fontproperties=font)
plt.show()