diff --git a/src/main/scala/fluence/hackethberlin/MakeVyperApp.scala b/src/main/scala/fluence/hackethberlin/MakeVyperApp.scala
index b34c6c2..44ace91 100644
--- a/src/main/scala/fluence/hackethberlin/MakeVyperApp.scala
+++ b/src/main/scala/fluence/hackethberlin/MakeVyperApp.scala
@@ -16,12 +16,11 @@ object MakeVyperApp extends App {
     ("address" → address) ::
       ("owner" → `public`(address)) ::
       ("holders" → (address ~>> bool)) ::
-      ("struct" → `public`(struct)) :: HNil
+      ("structMap" → `public`(Mapping(uint256, struct))) ::
+      ("struct" → `public`(struct)) ::
+      ("struct2" → struct) :: HNil
   )
 
-
   println(data.toVyper)
 
-  println(struct.toVyper)
-
 }
\ No newline at end of file
diff --git a/src/main/scala/fluence/hackethberlin/types/Mapping.scala b/src/main/scala/fluence/hackethberlin/types/Mapping.scala
index ac9356c..932355a 100644
--- a/src/main/scala/fluence/hackethberlin/types/Mapping.scala
+++ b/src/main/scala/fluence/hackethberlin/types/Mapping.scala
@@ -1,5 +1,5 @@
 package fluence.hackethberlin.types
 
-case class Mapping[K <: PrimitiveType, V <: Type](ktype: K, vtype: V) extends Type {
+case class Mapping[K <: PrimitiveType, V <: Type](ktype: K, vtype: V) extends PlainType {
   override def toVyper: String = s"${vtype.toVyper}[${ktype.toVyper}]"
 }
diff --git a/src/main/scala/fluence/hackethberlin/types/PrimitiveType.scala b/src/main/scala/fluence/hackethberlin/types/PrimitiveType.scala
index e4a436c..9ee8c84 100644
--- a/src/main/scala/fluence/hackethberlin/types/PrimitiveType.scala
+++ b/src/main/scala/fluence/hackethberlin/types/PrimitiveType.scala
@@ -1,6 +1,6 @@
 package fluence.hackethberlin.types
 
-abstract sealed class PrimitiveType(name: String) extends Type {
+abstract sealed class PrimitiveType(name: String) extends PlainType {
   self ⇒
 
   override def toVyper: String = name
diff --git a/src/main/scala/fluence/hackethberlin/types/StructType.scala b/src/main/scala/fluence/hackethberlin/types/StructType.scala
index 4d9d415..7382eb5 100644
--- a/src/main/scala/fluence/hackethberlin/types/StructType.scala
+++ b/src/main/scala/fluence/hackethberlin/types/StructType.scala
@@ -1,7 +1,7 @@
 package fluence.hackethberlin.types
 
-import shapeless.HList
+import shapeless.{HList, LUBConstraint}
 
-class StructType[D <: HList](dataDef: D)(implicit dv: DataVyper[D]) extends Type {
+class StructType[D <: HList](dataDef: D)(implicit dv: DataVyper[D], c: LUBConstraint[D, (String, PlainType)]) extends PlainType {
   override def toVyper: String = s"{${dv.toVyperDefinitions(dataDef).mkString(", ")}}"
 }
diff --git a/src/main/scala/fluence/hackethberlin/types/Type.scala b/src/main/scala/fluence/hackethberlin/types/Type.scala
index c08dc98..1fbe8ea 100644
--- a/src/main/scala/fluence/hackethberlin/types/Type.scala
+++ b/src/main/scala/fluence/hackethberlin/types/Type.scala
@@ -2,4 +2,6 @@ package fluence.hackethberlin.types
 
 trait Type {
   def toVyper: String
-}
\ No newline at end of file
+}
+
+trait PlainType extends Type
\ No newline at end of file