problems of gnuplot 5.4 when pipng commands from python

[<hua...@si...>]

Dear developers of gnuplot,First I want to thank you very much for developing such powerful tool.
I use gnuplot 5.4 in my own python program to check the results of some searching process.
the related code is like follows:
from subprocess import *  gnuplot= Popen(r"C:/Progra~1/gnuplot/bin/wgnuplot_pipes.exe", stdin = PIPE, stderr=PIPE,stdout=PIPE)  gnuplot.stdin.write(b"set terminal windows \n")  gnuplot.stdin.write(b"plot(sin(x)) \n")  gnuplot.stdin.flush()
input('Press the Return key to quit: ')  #pause gnuplot.stdin.close()  
In the above code, after Popen, the main gnuplot window is successfully launched.However, there is no any response for the next instructions, and nothing has happened.My Python version is 3.8.5
So how to solve the problem ?
Best regards,Wendong