I'm trying to configure Superset, but when I try to configure a new database to connect to oracle, I have problems,

Superset uses sqlalchemy for db connection, I define tnsname to connect and pass to superset as say documentation <http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html#database-urls>
oracle+cx\_oracle://ifn:XXXXXX@DBDESA but produces an error

(TypeError: expecting None or a string)

separatly i try to do a connection with sqlalchemy for test the connection

```
    Import sqlalchemy as sa
    Eng = sa.create_engine ('oracle + cx_oracle: // ifn: XXXXXX @ DBDESA')
    Eng.execute ('select 1 from dual') fetchall ()

```

But i get the same error, is there another needed configuration? Encoding or someting for connect to oracle XE? Or aditional params in superset configuration?

Tnsnames.ora

```
    DBDESA =
            (Description =
                    (Address_list =
            (Address = (protocol = TCP) (host = XXX.XX.X.X) (port = 1524)))
            (Connect_data = (Service_name = dbdesa)))

```