python - Copy file if it doesn't already exist

I'm fairly new to python, and I'm wondering how I can copy and paste a file from one location to another with first checking to see if the copied file exists in the destination folder?

The reason I want to check if the file exists is this script will be put on a task scheduler and run on a set schedule, so I don't want to be copying everything every single time, just those files that don't exist in the destination folder?

Thanks in advance!