Plotting multiple figures with subplots command only display the last figure in PythonPlot.jl

Plotting multiple figures with subplots command only display the last figure in both PythonPlot.jl and PyPlot.jl. Kindly run the program below.

using PythonPlot # Pyplot
pygui(true)

x = LinRange(0, 2*pi, 100)
f(x) = @. sin(x)
g(x) = @. cos(x)
h(x) = @. tan(x)

a1=subplots(3)
a1[1] = plot(x,f(x))
a1[2] = plot(x,g(x))
a1[3] = plot(x,h(x))