Why does sleep run before my code? - Python

Question

from guizero import App, Window, Drawing, PushButton, Text
from time import sleep

def redon():
    draw.oval (325, 550, 575, 800, color="#f70000")
def redoff():
    draw.oval (325, 550, 575, 800, color="#520404")
def greenon():
    draw.oval (325, 40, 575, 280, color="#08d10f")
def greenoff():
    draw.oval (325, 40, 575, 280, color="#072e04")
def greenblink():
    draw.oval (325, 40, 575, 280, color="#08d10f")
    sleep(1)
    draw.oval (325, 40, 575, 280, color="#072e04")
def yellowon():
    draw.oval (325, 540, 575, 290, color="yellow")
def yellowoff():
    draw.oval (325, 540, 575, 290, color="#59580b")
def blueon():
    draw.oval (55, 550, 305, 800, color = "#1594b0")
def blueoff():
    draw.oval (55, 550, 305, 800, color = "#0a3842")
def sequenceon():
    seq = True
    while seq == True:
        draw.oval (325, 40, 575, 280, color="#08d10f")  #green on
        for i in range(0, 5): #left turn blink
            draw.oval (55, 550, 305, 800, color = "#1594b0") #blue on
            sleep (0.5)
            draw.oval (55, 550, 305, 800, color = "#0a3842") #blue off
            sleep (0.5)
        draw.oval (325, 40, 575, 280, color="#072e04") #green off
        draw.oval (325, 540, 575, 290, color="yellow") #yellow on
        sleep (1)
        draw.oval (325, 550, 575, 800, color="#f70000") #red on
        sleep (1)
        draw.oval (325, 550, 575, 800, color="#520404") #red off
def sequenceoff():
    seq = False
    draw.oval (325, 550, 575, 800, color="#520404") #red off
    draw.oval (325, 40, 575, 280, color="#072e04") #green off
    draw.oval (55, 550, 305, 800, color = "#0a3842")#blue off
    draw.oval (325, 540, 575, 290, color="#59580b") #yellow off


main = App(title = "Traffic Light View", width=1000, height=1000)
draw = Drawing(main, width = 1000, height = 1000)
draw.rectangle (300,10,600,810, color = "black")
draw.oval (325, 40, 575, 280, color = "#072e04")
draw.oval (325, 540, 575, 290, color = "#59580b")
draw.oval (325, 550, 575, 800, color = "#520404")
draw.rectangle (45, 540, 315, 810, color="black")
draw.oval (55, 550, 305, 800, color = "#0a3842")
control = Window(main, title="Controller", layout = "grid", height="200", width="700")

greent = Text(control, "GREEN", grid=[0,1])
greenon1 = PushButton(control, text="Green Light - ON", command=greenon, grid=[0,2])
greenoff1 = PushButton(control, text="Green Light - OFF", command=greenoff, grid=[0,3])
greenblink1 = PushButton(control, text="Green Light -  Blink", command=greenblink, grid=[0,4])

yellowt = Text(control, "YELLOW", grid=[1,1])
yellowon1 = PushButton(control, text="Yellow Light - ON", command = yellowon, grid =[1,2])
yellowoff1 = PushButton(control, text="Yellow Light - OFF", command=yellowoff, grid=[1,3])

redt = Text(control, "RED", grid = [2,1])
redon1 = PushButton(control, text="Red Light - ON", command=redon, grid=[2,2])
redoff1 = PushButton(control, text="Red Light - OFF", command=redoff, grid=[2,3])

bluet = Text(control, "BLUE", grid= [3,1])
blueon1 = PushButton(control, text="Blue Light - ON", command=blueon, grid=[3,2])
blueoff1 = PushButton(control, text="Blue Light - OFF", command=blueoff, grid=[3,3])

sequencet =  Text(control, "SEQUENCE", grid=[4,1])
sequenceon1 = PushButton(control, text="Sequence - Start", command=sequenceon, grid=[4,2])
sequenceoff1 = PushButton(control, text = "Sequence - Stop", command=sequenceoff, grid=[4,3])
main.display()

When I run the code and click either the greenblink() or sequenceon() PushButtons, the button will hold down meaning the code is sleeping, it will then run the code that follows. Why does the sleep run ahead of all the other code in the function?

This code is written in python for use on a 3b rasberry pi.