diff --git a/src/qimp/ImageEncoding/QuantumImage.py b/src/qimp/ImageEncoding/QuantumImage.py
index 6b6232b..8f8baff 100644
--- a/src/qimp/ImageEncoding/QuantumImage.py
+++ b/src/qimp/ImageEncoding/QuantumImage.py
@@ -52,7 +52,7 @@ class QuantumImage(object):
     initial_qubits: int = 0
     x_wires: typing.List[int] = []
     y_wires: typing.List[int] = []
-    c_wire: int = 0
+    c_wire: typing.List[int] = []
     pos_wires: typing.List[int] = []
     total_wires: typing.List[int] = []
     n_aux_qubit: int = 0