diff --git a/src/ISA/ISA/ArcTypes/CompositeHeader.fs b/src/ISA/ISA/ArcTypes/CompositeHeader.fs
index 6e66b3fe..dca035c1 100644
--- a/src/ISA/ISA/ArcTypes/CompositeHeader.fs
+++ b/src/ISA/ISA/ArcTypes/CompositeHeader.fs
@@ -417,16 +417,21 @@ type CompositeHeader =
         | FreeText _ -> true
         | anythingElse -> false
 
-    member this.tryInput() =
+    member this.TryInput() =
         match this with
         | Input io -> Some io
         | _ -> None
 
-    member this.tryOutput() =
+    member this.TryOutput() =
         match this with
         | Output io -> Some io
         | _ -> None
 
+    member this.TryIOType() =
+        match this with
+        | Output io | Input io -> Some io
+        | _ -> None
+
     member this.TryParameter() = 
         match this with 
         | Parameter oa -> Some (ProtocolParameter.create(ParameterName = oa))