How to make python random.random() incorporate negatives

I'm trying to generate a pair of random numbers between -1 and 1.

I can make it go negative OR positive...but not generate a random number for x and y that may turn out negative as well as positive. Below is what I have (it's a dart throw simulation game from a website). randx and randy are where the random number generation is happening to be used as the coordinates.

import turtle
import math
import random

def main():

    fred = turtle.Turtle()
    fred.up()

    wn = turtle.Screen()
    wn.setworldcoordinates(-1,-1,1,1)

    numdarts = 10
    for i in range(numdarts):
        randx = random.random()
        randy = random.random()

        x = randx
        y = randy

        fred.goto(x,y)
        fred.stamp()

    wn.exitonclick()

main()