python how to add a figure legend at the best position

1# Short answer:
2# matplotlib.pyplot places the legend in the "best" location by default
3# To add a legend to your plot, call plt.legend()
4
5# Example usage:
6import matplotlib.pyplot as plt
7x1 = [1, 2, 3] # Invent x and y data to be plotted
8y1 = [4, 5, 6]
9x2 = [1, 3, 5]
10y2 = [6, 5, 4]
11
12plt.plot(x1, y1, label="Dataset_1") # Use label="data_name" so that the 
13									# legend is easy to interpret
14plt.plot(x2, y2, label="Dataset_2")
15plt.legend(loc='best')
16plt.show()
17
18# Other legend locations you can specify:
19Location String		Location Code (e.g. loc=1)
20'best'				0
21'upper right'		1
22'upper left'		2
23'lower left'		3
24'lower right'		4
25'right'				5
26'center left'		6
27'center right'		7
28'lower center'		8
29'upper center'		9
30'center'			10