So, I run this code and everything works out fine expect the stars are not fully colored. Can you guys tell me why that is? Thanks you

import turtle as tu
import random as rn

def draw_star (x,y,color, side):
    tu.color(color)
    tu.begin_fill()
    tu.penup()
    tu.goto(x, y)
    tu.pendown()
    for k in range(5):
        tu.forward (side)
        tu.right(144)
        tu.forward (side)
    tu.end_fill()

def random_length():
    return rn.randrange(40, 70)
def random_xy_coord():
    return rn.randrange(-300,300), rn.randrange(-300, 300)

tu.title('Star')
tu.bgcolor('black')

tu.speed('fast')
colors = ['red','orange','magenta','green','blue','yellow','white']

stars = 10
for k in range(stars):
    color= rn.choice(colors)
    side = random_length()
    x, y = random_xy_coord()
    draw_star(x,y,color,side)

tu.done()