I tried to import turtle and I tried to write sc turtle Screen but it gives attribute error in these

Question

import turtle
  
# make screen object
# and set size
sc = turtle.Screen()
sc.setup(400,300)
  
# make turlte object
t1=turtle.Turtle(shape='square')
  
# do some motion with properties
t1.color("red")
t1.circle(50)
  
# make another turlte object
t2=turtle.Turtle(shape='circle')
  
# do some motion with properties
t2.color("green")
t2.circle(40)
  
# get all turtle objects on screen
print(sc.turtles())