'Interrogate Django environment for specific settings values
:param django_setting: the django setting to get
:param system: the django app to use when asking for the setting (lms | cms)
:param settings: the settings file to use when asking for the value
:return: unicode value of the django setting'

@classmethod
def get_django_setting(self, django_setting, system, settings=None):

    if (not settings):
        settings = os.environ.get('EDX_PLATFORM_SETTINGS', 'aws')
    value = sh(django_cmd(system, settings, 'print_settings    {django_setting}    --format=value    2>/dev/null'.format(django_setting=django_setting)), capture=True)
    return unicode(value).strip()
