python - settings.database is improperly configured when using Amazon RDS postgres database -

i using django , when load code works when signing admin login. when proceeding after logging in comes database being improperly configured please specify engine value. have added else statement , have tried using local database it. comes 500 http error whenever add in local database. help!

if 'database' in os.environ:  databases = {  'default': {     'engine': 'django.db.backends.postgresql_psycopg2',     'name': os.environ['database'],      'user': os.environ['datauser'],      'password': os.environ['data!aa'],     'host': os.environ['xxxxxxxxxxxxxxxxxxxxxxxxxxx'],      'port': os.environ['xxxx'],     } } 

i using mac(osx)