Trouble with pyroot about drawing a function

ROOT Version: 6.26
Platform: MacOS Catalina

I am newbie in HEP and I was trying to use root with python so, when I use python prompt like below I get the graph like this

Nonetheless, I am not able to get the same graph when I try to execute the script,

I really appreciate it for any help

python3 -i ...

Then graph don’t show up either and I am getting this:

After the “Draw”, try to add: ROOT.gPad.Modified(); ROOT.gPad.Update()

Thank you it worked but is there any way to do without “python3 -i …