Python name 'os' is not defined

I am trying to run this python module

from settings import PROJECT_ROOT

DEBUG = True
TEMPLATE_DEBUG = DEBUG


DATABASES = {
    'default': {
        'ENGINE':  'django.db.backends.sqlite3',
        'NAME' : os.path.join(BASE_DIR, 'db_name.sqlite3'),
    }
}


# Make this unique, and don't share it with anybody.
SECRET_KEY = 'sdfgtardyure34654356435'

# Python dotted path to the WSGI application used by Django's runserver; added in v1.4
WSGI_APPLICATION = 'wsgi.application'

############### PYSEC specific variables

# assumes this directory exists
DATA_DIR = "%s/pysec/data/" % PROJECT_ROOT

But whenever i try to run it by F5 i get this

Traceback (most recent call last):
  File "C:\Python27\pysec-master\local_settings-example.py", line 11, in <module>
    'NAME' : os.path.join(BASE_DIR, 'db_name.sqlite3'),
NameError: name 'os' is not defined

The module lives in the C:\Python27\pysec-master and i got pysec for here

Do you know what must i do to run the module with success?

Just add:

import os

in the beginning, before:

from settings import PROJECT_ROOT

This will import the python's module os, which apparently is used later in the code of your module without being imported.

The problem is that you forgot to import os. Add this line of code:

import os

And everything should be fine. Hope this helps!