How to adjust the size of matplotlib legend box?

Question

I have a graph whose left upper corner is quite blank. So I decide to put my legend box there.

However, I find the items in legend are very small a

Answer 1

When you call legend you can use the prop argument with a dict containing size.

plt.errorbar(x, y, yerr=err, fmt='-o', color='k', label = 'DR errors')
plt.legend(prop={'size':50})

E.g.

See here for more info on legend