If your runtime machine have scp installed. You can simply launch scp command from python, it's the simpler. But scp will ask you to give a password each time, that's why I recommend the folowing approach:
1) Generate a RSA keypair on your runtime machine: launch that on bash and follow instructions, it's up to you to decide if you use a passphrase:
ssh-keygen
You will now have .pub file where you decided to store the key. add the content of this .pub in the following file of your raspberry pi:
~/.ssh/authorized_keys
Obviously, create the .ssh folder and the file if they don't exists. if authorized_keys exists, append the .pub content at his end after a new line so you won't override it current content. Once this is done, your raspberry pi will trust your computer and won't ask for a password when someone connect with that key you generated (so keep it secret!). If you prefer type your password each time your script is runned, then just don't add this key to authorized_keys.
now in your python script:
import os
cmd = os.popen('scp <USER>@<YOUR_MACHINE_ADDRESS>:<LOCATION_OF_THE_REMOTE_FILE> <LOCATION_TO_STORE_IT>')
cmd.read()
That will copy from your raspberry pi to your computer, if you wants to do the opposite, switch the two arguments of scp.
Obviously, it's up to you to create logical structures around the command to determine wich argument you will give to it and in wich case you execute it. Know that using os.popen(), the program will block until the command has finished, and that the command won't be executed untill cmd.read() is called
If you don't like this method, you may have a look here and the links provided in this question
