diff --git a/qiskit/circuit/library/data_preparation/state_preparation.py b/qiskit/circuit/library/data_preparation/state_preparation.py
index 4c5a10320e4..37b3cc05cfb 100644
--- a/qiskit/circuit/library/data_preparation/state_preparation.py
+++ b/qiskit/circuit/library/data_preparation/state_preparation.py
@@ -535,7 +535,7 @@ def _define(self):
         return qc
 
     def M(self):
-        """Returns the M value used by the gate"
+        """Returns the M value used by the gate"""
         return self._M
     
     def num_qubits(self):