c310 logitech webcam not closing properly in pygame code

Question

I'm accessing my c310 logitech webcam in python with pygame in an attempt to take pictures and save them. My final goal is to take a new picture every minute for 24 hours to make a timelapse. Here is the code to take a single picture:

#!/usr/bin/python
import os
import pygame, sys
import time

from pygame.locals import *
import pygame.camera

#initialize pygame
pygame.init()
pygame.camera.init()   
cam = pygame.camera.Camera('/dev/video0')

cam.start()

#take a picture
image = cam.get_image()


x = 1
#save picture
alpha = 'picture%d.jpg' % (x)
pygame.image.save(image, alpha)

cam.stop()
pygame.quit()

My issue is that after running this code from the command prompt and then attempting to run the code again (even after waiting several seconds), I get the error:

 Traceback (most recent call last):
  File "Picture1.py", line 13, in <module>
    cam.start()
SystemError: Cannot open '/dev/video0': 16, Device or resource busy

I'm not sure why I get this error, as I use cam.stop() and pygame.quit() at the end of my code, so nothing should be using the camera after I run it. Everything is updated. Has anyone run into this error before?