AtrributeError with basic sprite collision - pygame

Question

Just started with sprite collision in pygame. When this code is run, an AttributeError pops up that says ''Group' object has no attribute 'rect''. I can't figure out why this error occurs. Suggestions?
from random import randint
import pygame
pygame.init()
white = [255,255,255]
blue = [0,0,255]
red = [255,0,0]
size = (400,400)
screen = pygame.display.set_mode(size)
pygame.display.set_caption('Simple character')
clock = pygame.time.Clock()
class Ball(pygame.sprite.Sprite):
def __init__(self, xDelta, yDelta, color):
pygame.sprite.Sprite.__init__(self)
self.image = pygame.Surface([20,20])
self.image.fill(white)
self.image.set_colorkey(white)
self.xDelta = xDelta
self.yDelta = yDelta
self.color = color
self.rect = self.image.get_rect()
pygame.draw.circle(self.image, self.color,
[(self.rect.x + 10), (self.rect.y + 10)], 10)
def update(self):
self.rect.x += self.xDelta
self.rect.y += self.yDelta
if self.rect.y <= 0 or self.rect.y >= 380:
self.yDelta *= -1
if self.rect.x >= 380 or self.rect.x <= 0:
self.xDelta *= -1
allSprites = pygame.sprite.Group()
blues = pygame.sprite.Group()
reds = pygame.sprite.Group()
for i in range(5):
circle = Ball(randint(1, 10), randint(1, 10), blue)
circle.rect.x = randint(0,380)
circle.rect.y = randint(0,380)
blues.add(circle)
allSprites.add(circle)
circle2 = Ball(randint(1, 10), randint(1, 10), red)
circle2.rect.x = randint(0,380)
circle2.rect.y = randint(0,380)
reds.add(circle2)
allSprites.add(circle2)
play = True
while play:
clock.tick(20)
for event in pygame.event.get():
if event.type == pygame.QUIT:
play = False
allSprites.update()
collision = pygame.sprite.spritecollide(blues, reds, True)
for circle in collision:
circle.xDelta = circle.yDelta = 0
screen.fill(white)
allSprites.draw(screen)
pygame.display.flip()
pygame.quit()

Answer 1

You are calling spritecollide on two objects of class Group. The function takes a Sprite and a Group.
spritecollide(sprite, group, dokill, collided = None) -> Sprite_list
What you could do is loop through all the blues sprites, and call spritecollide with one blue ball.
for blueball in blues.sprites:
collision = pygame.sprite.spritecollide(blues, reds, True)
for circle in collision:
circle.xDelta = circle.yDelta = 0