diff --git a/crates/aiken-lang/src/uplc.rs b/crates/aiken-lang/src/uplc.rs
index 697daf00..269ca214 100644
--- a/crates/aiken-lang/src/uplc.rs
+++ b/crates/aiken-lang/src/uplc.rs
@@ -756,16 +756,29 @@ impl<'a> CodeGenerator<'a> {
                         scope.clone(),
                     );
 
-                    let data_type =
-                        lookup_data_type_by_tipo(self.data_types.clone(), subject_type).unwrap();
+                    let data_type = lookup_data_type_by_tipo(self.data_types.clone(), subject_type);
 
-                    if data_type.constructors.len() > 1 {
-                        ir_stack.push(Air::Clause {
-                            scope,
-                            tipo: subject_type.clone(),
-                            complex_clause: *clause_properties.is_complex_clause(),
-                            subject_name,
-                        });
+                    if let Some(data_type) = data_type {
+                        if data_type.constructors.len() > 1 {
+                            ir_stack.push(Air::Clause {
+                                scope,
+                                tipo: subject_type.clone(),
+                                complex_clause: *clause_properties.is_complex_clause(),
+                                subject_name,
+                            });
+                        } else {
+                            ir_stack.push(Air::Clause {
+                                scope: scope.clone(),
+                                tipo: subject_type.clone(),
+                                complex_clause: *clause_properties.is_complex_clause(),
+                                subject_name,
+                            });
+
+                            ir_stack.push(Air::Int {
+                                scope,
+                                value: "0".to_string(),
+                            });
+                        }
                     } else {
                         ir_stack.push(Air::Clause {
                             scope: scope.clone(),
@@ -773,11 +786,6 @@ impl<'a> CodeGenerator<'a> {
                             complex_clause: *clause_properties.is_complex_clause(),
                             subject_name,
                         });
-
-                        ir_stack.push(Air::Int {
-                            scope,
-                            value: "0".to_string(),
-                        });
                     }
                 }
                 ClauseProperties::ListClause {
diff --git a/examples/acceptance_tests/067/aiken.lock b/examples/acceptance_tests/067/aiken.lock
index 550023f7..0423f31b 100644
--- a/examples/acceptance_tests/067/aiken.lock
+++ b/examples/acceptance_tests/067/aiken.lock
@@ -3,11 +3,11 @@
 
 [[requirements]]
 name = "aiken-lang/stdlib"
-version = "3b47c89006e7580c2213370d7426ed2a38d2836e"
+version = "main"
 source = "github"
 
 [[packages]]
 name = "aiken-lang/stdlib"
-version = "3b47c89006e7580c2213370d7426ed2a38d2836e"
+version = "main"
 requirements = []
 source = "github"
diff --git a/examples/acceptance_tests/067/aiken.toml b/examples/acceptance_tests/067/aiken.toml
index da735dea..c7a4ff60 100644
--- a/examples/acceptance_tests/067/aiken.toml
+++ b/examples/acceptance_tests/067/aiken.toml
@@ -1,6 +1,8 @@
 name = "aiken-lang/acceptance_test_067"
-version = "0.0.0"
+version = '0.0.0'
+description = ''
 
-dependencies = [
-  { name = "aiken-lang/stdlib", version = "3b47c89006e7580c2213370d7426ed2a38d2836e", source = "github" },
-]
+[[dependencies]]
+name = 'aiken-lang/stdlib'
+version = 'main'
+source = 'github'
diff --git a/examples/acceptance_tests/067/lib/tests.ak b/examples/acceptance_tests/067/lib/tests.ak
index c8207082..aed1da34 100644
--- a/examples/acceptance_tests/067/lib/tests.ak
+++ b/examples/acceptance_tests/067/lib/tests.ak
@@ -54,7 +54,7 @@ test to_list_1() {
 // Function returning a hash of a given Merkle Tree element
 pub fn root_hash(self: MerkleTree<a>) -> Hash<Sha2_256, ByteArray> {
   when self is {
-    Empty -> #""
+    Empty -> ""
     Leaf { hash, .. } -> hash
     Node { hash, .. } -> hash
   }
@@ -579,6 +579,6 @@ fn get_proof_item_value(proof_item: ProofItem) -> Hash<Sha2_256, ByteArray> {
   }
 }
 
-fn create_string_item_hash_fn() -> fn(String) -> Hash<Sha2_256, String> {
-  fn(x: String) { sha2_256(from_string(x)) }
+fn create_string_item_hash_fn() -> fn(ByteArray) -> Hash<Sha2_256, String> {
+  fn(x: ByteArray) { sha2_256(x) }
 }