Draw a rainbow

# import package and making objects
import turtle

sc = turtle.Screen()
trtl = turtle.Turtle()


# method to draw y-axis lines
def drawy(val):
    # line
    trtl.forward(300)

    # set position
    trtl.up()
    trtl.setpos(val, 300)
    trtl.down()

    # another line
    trtl.backward(300)

    # set position again
    trtl.up()
    trtl.setpos(val + 10, 0)
    trtl.down()


# method to draw y-axis lines
def drawx(val):
    # line
    trtl.forward(300)

    # set position
    trtl.up()
    trtl.setpos(300, val)
    trtl.down()

    # another line
    trtl.backward(300)

    # set position again
    trtl.up()
    trtl.setpos(0, val + 10)
    trtl.down()


# method to label the graph grid
def lab():
    # set position
    trtl.penup()
    trtl.setpos(155, 155)
    trtl.pendown()

    # write 0
    trtl.write(0, font=("Verdana", 12, "bold"))

    # set position again
    trtl.penup()
    trtl.setpos(290, 155)
    trtl.pendown()

    # write x
    trtl.write("x", font=("Verdana", 12, "bold"))

    # set position again
    trtl.penup()
    trtl.setpos(155, 290)
    trtl.pendown()

    # write y
    trtl.write("y", font=("Verdana", 12, "bold"))


# Main Section
# set screen
sc.setup(800, 800)

# set turtle features
trtl.speed(100)
trtl.left(90)
trtl.color('lightgreen')

# y lines
for i in range(30):
    drawy(10 * (i + 1))

# set position for x lines
trtl.right(90)
trtl.up()
trtl.setpos(0, 0)
trtl.down()

# x lines
for i in range(30):
    drawx(10 * (i + 1))

# axis
trtl.color('green')

# set position for x axis
trtl.up()
trtl.setpos(0, 150)
trtl.down()

# x-axis
trtl.forward(300)

# set position for y axis
trtl.left(90)
trtl.up()
trtl.setpos(150, 0)
trtl.down()

# y-axis
trtl.forward(300)

# labeling
lab()

# hide the turtle
trtl.hideturtle()
turtle.Screen().exitonclick()