diff --git a/odc/stats/plugins/l34_utils/l4_water_persistence.py b/odc/stats/plugins/l34_utils/l4_water_persistence.py
index 53457e4..680480e 100644
--- a/odc/stats/plugins/l34_utils/l4_water_persistence.py
+++ b/odc/stats/plugins/l34_utils/l4_water_persistence.py
@@ -14,7 +14,11 @@ def water_persistence(xx: xr.Dataset, watper_threshold):
         {"a": xx.water_frequency.data},
         name="mark_water",
         dtype="uint8",
-        **{"m": watper_threshold[3], "nodata": NODATA, "water_freq_nodata": WATER_FREQ_NODATA},
+        **{
+            "m": watper_threshold[3],
+            "nodata": NODATA,
+            "water_freq_nodata": WATER_FREQ_NODATA,
+        },
     )
 
     #  10 <= water_frequency < 1 --> 1