returning non nil potentially void dictionary

modules/swagger-codegen/src/main/resources/swift/APIHelper.mustache

@@ -18,4 +18,20 @@ class APIHelper {
         }
         return destination
     }
+
+    static func convertBoolToString(source: [String: AnyObject]) -> [String:AnyObject] {
+        var destination = [String:AnyObject]()
+        let theTrue = NSNumber(bool: true)
+        let theFalse = NSNumber(bool: false)
+        for (key, value) in source {
+            switch value {
+                case let x where x === theTrue || x === theFalse:
+                    destination[key] = "\(value as! Bool)"
+                default:
+                    destination[key] = value
+            }
+        }
+        return destination
+    }
+
 }