There are two possible points of failure here: First, do you have Python installed on your computer? TeX is not magic,
python.sty relies on an external Python interpreter rather than parsing and interpreting the Python code itself (which is theoretically possible but implausible and would likely be impractical if it were actually implemented).
Assuming you have Python, your second point of failure is that the default configuration of TeX is to not allow shell escapes. There are two ways to do this: One is to add
-shell-escape to the LaTeX command to turn it on. Alternatively, you can make shell escape available to all runs of LaTeX by editing
texmf.cnf and adding
shell_escape = t to that file. Except since you're using MikTeX, it's a bit different. You'll use the command
(assuming it's pdflatex that you're using) to edit the settings). I can't address this too specifically since I'm a Mac guy, but I'd suggest digging into https://docs.miktex.org for the full story.