plt text background alpha

1import numpy as np
2import matplotlib.pyplot as plt
3plt.figure()
4ax = plt.subplot(111)
5plt.plot(np.linspace(1,0,1000))
6t = plt.text(0.03,.95,'text',transform=ax.transAxes,backgroundcolor='0.75',alpha=.5)
7plt.show()

1plt_text = plt.text(
2	0.5,  # x
3    0.5,  # y
4    'your text',  # text
5    fontsize=30
6)
7plt_text.set_bbox(dict(
8	facecolor='red',  # background color
9    alpha=0.5,  # background alpha
10    edgecolor='red'  # border color
11))