Django and Oracle

I have a django project that I need to connect to an Oracle database

When I use sqlite3, which comes by default with the following string:

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

The application works without problems but when I connect with oracle with the following string:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.oracle',
        'NAME': 'DBARS_PROD',
        'USER': 'userhere',
        'PASSWORD': 'passhere',


        }
}

django returns the following error:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\commands\runserver.py", line 62, in execute
    super(Command, self).execute(*args, **options)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\commands\runserver.py", line 101, in handle
    self.run(**options)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\core\management\commands\runserver.py", line 110, in run
    autoreload.main(self.inner_run, None, options)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\utils\autoreload.py", line 332, in main
    reloader(wrapped_main_func, args, kwargs)
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\utils\autoreload.py", line 303, in python_reloader
    exit_code = restart_with_reloader()
  File "C:\Users\nbueno\Envs\nworksdev\lib\site-packages\django\utils\autoreload.py", line 289, in restart_with_reloader
    exit_code = subprocess.call(args, env=new_environ)
  File "c:\python27\Lib\subprocess.py", line 523, in call
    return Popen(*popenargs, **kwargs).wait()
  File "c:\python27\Lib\subprocess.py", line 711, in __init__
    errread, errwrite)
  File "c:\python27\Lib\subprocess.py", line 959, in _execute_child
    startupinfo)
TypeError: environment can only contain strings

But if I run the command python manage.py test to test the connection, I'll see that everything is correct:

Creating test database for alias 'default'...
Creating test user...
System check identified no issues (0 silenced).

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK
Destroying test database for alias 'default'...
Destroying test user...
Destroying test database tables...

It seems that when django query oracle it returns unicode and no strings. or does anyone know what is due?