if no arguments, return error at once

main.go

@@ -44,7 +44,8 @@ func Open(dialect string, args ...interface{}) (*DB, error) {
 
 	if len(args) == 0 {
 		err = errors.New("invalid database source")
-	} else {
+		return nil, err
+	}
 	var source string
 	var dbSQL sqlCommon
 
@@ -79,7 +80,6 @@ func Open(dialect string, args ...interface{}) (*DB, error) {
 			db.DB().Close()
 		}
 	}
-	}
 
 	return &db, err
 }