Python 3.3.1 (default, Apr 17 2013, 22:32:14) 
[GCC 4.7.3]
Type "help", "copyright", "credits" or "license" for more information.
from turtle import Turtle
t1 = Turtle()
t1.pos()
(0.00,0.00)
t1.forward(30)
t1.left(90)
t1.forward(40)
t1.pos()
(30.00,40.00)
t1.distance()
Traceback (most recent call last):
  File "<string>", line 1, in <fragment>
builtins.TypeError: distance() missing 1 required positional argument: 'x'
t1.modulus()
Traceback (most recent call last):
  File "<string>", line 1, in <fragment>
builtins.AttributeError: 'Turtle' object has no attribute 'modulus'
t1.neck
Traceback (most recent call last):
  File "<string>", line 1, in <fragment>
builtins.AttributeError: 'Turtle' object has no attribute 'neck'
Turtle.neck = "green and articulated"
t2 = Turtle()
t2.neck
'green and articulated'
def modulus(turt):
   pass

from math import sqrt
def modulus(turt):
   return sqrt(turt.pos()[0]**2 + turt.pos()[1]**2)

modulus(t2)
0.0
t2.forward(30)
t2.left(90)
modulus(t2)
30.0
t2.forward(40)
modulus(t2)
50.0
t2.modulus()
Traceback (most recent call last):
  File "<string>", line 1, in <fragment>
builtins.AttributeError: 'Turtle' object has no attribute 'modulus'
Turtle.modulus = modulus
t3 = Turtle()
t3.forward(40)
t3.left(90)
t3.forward(30)
t3.modulus()
50.0