diff --git a/mers/Cargo.toml b/mers/Cargo.toml
index abc024e..95e9f4b 100644
--- a/mers/Cargo.toml
+++ b/mers/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mers"
-version = "0.9.28"
+version = "0.9.29"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "dynamically typed but type-checked programming language"
@@ -15,7 +15,7 @@ default = ["colored-output"]
 colored-output = ["mers_lib/ecolor-term", "mers_lib/pretty-print", "dep:colored"]
 
 [dependencies]
-mers_lib = "0.9.28"
+mers_lib = "0.9.29"
 # mers_lib = { path = "../mers_lib" }
 clap = { version = "4.3.19", features = ["derive"] }
 colored = { version = "2.1.0", optional = true }
diff --git a/mers_lib/Cargo.toml b/mers_lib/Cargo.toml
index 3a8cc96..ce78f9b 100755
--- a/mers_lib/Cargo.toml
+++ b/mers_lib/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "mers_lib"
-version = "0.9.28"
+version = "0.9.29"
 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/defs.rs b/mers_lib/src/data/defs.rs
index b86f3ff..69d84f4 100755
--- a/mers_lib/src/data/defs.rs
+++ b/mers_lib/src/data/defs.rs
@@ -17,8 +17,8 @@ pub fn assign(from: &Data, target: &Data) {
                     .as_any()
                     .downcast_ref::<crate::data::reference::Reference>()
                     .and_then(|r| {
-                        r.read()
-                            .get()
+                        r.write()
+                            .get_mut()
                             .as_any()
                             .downcast_ref::<crate::data::tuple::Tuple>()
                             .map(|v| (v.clone_refs(), true))
@@ -46,8 +46,8 @@ pub fn assign(from: &Data, target: &Data) {
                     .as_any()
                     .downcast_ref::<crate::data::reference::Reference>()
                     .and_then(|r| {
-                        r.read()
-                            .get()
+                        r.write()
+                            .get_mut()
                             .as_any()
                             .downcast_ref::<crate::data::object::Object>()
                             .map(|v| (v.clone_refs(), true))