def dice(number, sides=6):
    total = 0
    for _ in range(number):
        total += random.randrange(1, sides+1)
    return total

# I'm calling randrange once _each time through the loop_,
# so I'm getting <number> different random numbers, and
# adding them together. (I used randrange instead of choice
# so you don't have to keep around a list of 4 numbers for
# a d4, and a list of 6 numbers for a d6, and so on.)

# Use it like this:

strength = dice(3, 6)
intelligence = dice(3, 6)
wisdom = dice(3, 6)
dexterity = dice(3, 6)
constitution = dice(3, 6)
charisma = dice(3, 6)

# Each of these six variables will end up with a different
# number from 3-18. (Well, it's _possible_ they'll all be
# the same, just rare--just as it's possible, but rare, to
# roll the same number over and over with real dice.)

###

# A cleaner and more idiomatic implementation might be:

def die(sides=6):
    return random.randrange(1, sides+1)

def dice(number, sides=6):
    return sum(die(sides) for _ in range(number))

# You use it the exact same way