diff --git a/pyhealth/metrics/calibration.py b/pyhealth/metrics/calibration.py
index 32e27b617..d9f755f61 100644
--- a/pyhealth/metrics/calibration.py
+++ b/pyhealth/metrics/calibration.py
@@ -99,7 +99,7 @@ def _ECE_classwise(prob:np.ndarray, label_onehot:np.ndarray, bins=20, threshold=
     return summs, class_losses
 
 def ece_confidence_multiclass(prob:np.ndarray, label:np.ndarray, bins=20, adaptive=False):
-    """Expected Calibration Error (ECE).
+    r"""Expected Calibration Error (ECE).
 
     We group samples into 'bins' basing on the top-class prediction.
     Then, we compute the absolute difference between the average top-class prediction and