Problem is setting programming environment

Hello, I have a problem in setting programming environment and in the step " Create a Device Identity". When I run command: “python3 stdk-keygen.py --firmware switch_example_001” I got this error:
Traceback (most recent call last):
File “stdk-keygen.py”, line 13, in
from nacl.signing import SigningKey, VerifyKey
ImportError: No module named ‘nacl’

I tried to install pynacl using pip but I got some errors.

Welcome to the SmartThings Community, @fatehi.a5391!
Are you following the guide included in this post?

Which device are you using?

programming environment is setting up your local machine to do practice/development. Example, if you planned to learn python, you must have some local setup to practice python. Those setup is called programming environment. Once it’s done we can do our work without any interruption.