how to change pen size in python turtle code example

Example 1: turtle python

from turtle import *
color('red', 'yellow')
begin_fill()
while True:
    forward(200)
    left(170)
    if abs(pos()) < 1:
        break
end_fill()
done()

Example 2: how to import turtle in Python

import turtle
win = turtle.Screen()

Example 3: turtle write

turtle.write(arg, move=False, align="left", font=("Arial", 8, "normal"))

Example 4: setheading in python

turtle.setheading(direction) #set the direction for turtle