Why Pyplot in VScode shows nothing?

Hi,

I’m trying t run the following code:

using PyPlot

# Preparing a figure object
fig = figure()

# Data
x = range(0, stop=2*pi, length=1000)
y = sin.(3*x)

# Plotting with linewidth and linestyle specified
plot(x, y, color="blue", linewidth=2.0, linestyle="--")

# Labeling the axes
xlabel(L"value of $x$")
ylabel(L"\sin(3x)")

# Title
title("Test plotting")
display(gcf())

I have both plot pane and pop up window, but no figure is displayed in VS code. Why it shows nothing?