diff --git a/src/core/convert/_keys_to_parity.js b/src/core/convert/_keys_to_parity.js
index 577e384..c70c517 100644
--- a/src/core/convert/_keys_to_parity.js
+++ b/src/core/convert/_keys_to_parity.js
@@ -27,7 +27,7 @@ export default function _keys_to_parity(clauses) {
 			new_clause.add(literal);
 		}
 
-		instance.push([...new_clause]);
+		instance.push(Array.from(new_clause));
 	}
 
 	return new KeysInstance(variables, instance);