how to capture folder as input and pass it to python script as argument
You need to tell it where to put the arguments.

for f in "$@"
do
    "/usr/local/bin/python" -i -o "~/Development/python/slideShow/scripts/slideshow" "$f"
done


…or, if you're only ever going to select one folder, you can simplify it a bit:

"/usr/local/bin/python" -i -o "~/Development/python/slideShow/scripts/slideshow" "$@"