Problem with importing an installed package

[Reverend_Jim]

I installed pymsgbox using pip. I created a sample file that does only

import pymsgbox
pymsgbox.alert("some text")

When I run it from the command line (like most of my scripts) by typing "sample" I just get "ModuleNotFoundError: No module named 'pymsgbox'". When I run it by typing "python sample.py", or when I run it through IDLE, or when I run python.exe and type the code in manually, everything runs just fine. Can someone suggest how to fix this (I suspect a config problem of some sort)?