I have a question related with the connections. I am using the following code for that:

     connection = connectionForURI('postgres://'+user+':'+password+'@'+host+'/'+database)
     sqlhub.processConnection = connection
     connection.query("SELECT 1")
except OperationalError:
     print "error"

but, I don't know if the error is because the user and password are wrong or the sever is not working. How can I verify that? for example, maybe, with a error code but I don't know how to get it.