diff --git a/mers_lib/Cargo.toml b/mers_lib/Cargo.toml
index d291727..018c209 100755
--- a/mers_lib/Cargo.toml
+++ b/mers_lib/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mers_lib"
-version = "0.6.0"
+version = "0.6.1"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "library to use the mers language in other projects"
diff --git a/mers_lib/src/data/mod.rs b/mers_lib/src/data/mod.rs
index ca93af5..1b5ae1e 100755
--- a/mers_lib/src/data/mod.rs
+++ b/mers_lib/src/data/mod.rs
@@ -298,15 +298,18 @@ impl Type {
     pub fn add(&mut self, new: Arc<dyn MersType>) {
         let n = new.as_any();
         if let Some(s) = n.downcast_ref::<Self>() {
-            for t in &s.types {
-                self.add(Arc::clone(t));
-            }
+            self.add_all(s);
         } else {
             if !self.types.iter().any(|t| new.is_included_in(t.as_ref())) {
                 self.types.push(new);
             }
         }
     }
+    pub fn add_all(&mut self, types: &Self) {
+        for t in &types.types {
+            self.add(Arc::clone(t));
+        }
+    }
     pub fn dereference(&self) -> Option<Self> {
         let mut o = Self::empty();
         for t in &self.types {