matplotlib---在figure中为多副子图添加一个legend（图例）

参考：https://*.com/questions/9834452/how-do-i-make-a-single-legend-for-many-subplots-with-matplotlib

https://zhuanlan.zhihu.com/p/35983270

https://zhuanlan.zhihu.com/p/36004578

https://www.zhihu.com/people/yang-fan-27-12/posts?page=3

from matplotlib import rcParams
params={'font.family':'serif',
        'font.serif':'Times New Roman',
        'font.style':'normal',
        'font.weight':'normal', #or 'blod'
        'font.size':'9',#or large,small,9==小五
        }
rcParams.update(params)

import matplotlib.lines as mlines
blue_line = mlines.Line2D([], [], color=Color[0], marker='.',
                          markersize=10, label='Blue stars')
fig.legend(handles=[blue_line]).get_frame().set_linewidth(0)