bug: Standard plot doesn't work

[taoluo]

Environment data

VS Code version: 1.18.1 Jupyter Extension version: 1.1.4 OS and version: mac osx

Actual behavior

result pane shows the following

[<matplotlib.lines.Line2D at 0x1194f05f8>]
Unknown Mime Type

Expected behavior

inline plot from matplotlib

Steps to reproduce:

#%%
import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np

x = np.linspace(0, 20, 100)
plt.plot(x, np.sin(x))```