diff --git a/utils/timefeatures.py b/utils/timefeatures.py
index 0c17fca..63f9bfa 100644
--- a/utils/timefeatures.py
+++ b/utils/timefeatures.py
@@ -55,7 +55,7 @@ class MonthOfYear(TimeFeature):
 
 class WeekOfYear(TimeFeature):
     """Week of year encoded as value between [-0.5, 0.5]"""
-    def __call__(self, index: pd.DatetimeIndex) -> np.ndarray:
+    def __call__(self, index: pd.DatetimeIndex) -> mnp.ndarray:
         return (index.week - 1) / 52.0 - 0.5
 
 def time_features_from_frequency_str(freq_str: str) -> List[TimeFeature]: