Why does the turtle module in Python appear to have a screen attribute when trying to access it results in an attribute error?

Question

The following is a script attempting to draw a turtle graphic using the Python turtle module.

import turtle

wn = turtle.screen()

alex = turtle.Turtle()

alex.forward(50)

alex.left(90)

alex.forward(30)

wn.mainloop()

At runtime, the script produces the following traceback (with generic path to script).

Traceback (most recent call last):
  File "</path/to/script>.py", line <number>, in <module>
    wn = turtle.screen()
AttributeError: module 'turtle' has no attribute 'screen'

It appears that the turtle module has a screen attribute in its documentation. That being the case, why does this AttributeError occur?

Answer 1

You're getting the error

Traceback (most recent call last):
  File "</path/to/script>.py", line <number>, in <module>
    wn = turtle.screen()
AttributeError: module 'turtle' has no attribute 'screen'

because the turtle library doesn't have an attribute screen, but this is just a minor typo as the turtle library does have a Screen attribute. The Python programming language cares about the case of letters, which is often described as case-senstive syntax or case sensitivity.