Django: Environment variable in Django settings

get-env-variable.py

# Load environment variable into Django settings.
# Usage: SOME_SECRET_KEY = get_env_variable("SOME_SECRET_KEY")

import os
from django.core.exceptions import ImproperlyConfigured

def get_env_variable(var_name):
    """ Get the environment variable or return exception """
    try:
        return os.environ[var_name]
    except KeyError:
        error_msg = "Set the %s environment variable" % var_name
        raise ImproperlyConfigured(error_msg)