diff --git a/geomagio/residual/Reading.py b/geomagio/residual/Reading.py
index a52adb9caa011c43a010726526fe14a97cee675a..752ffc4b0c4d778072584b2de468785444f61f52 100644
--- a/geomagio/residual/Reading.py
+++ b/geomagio/residual/Reading.py
@@ -38,7 +38,7 @@ class Reading(BaseModel):
     measurements: List[Measurement] = []
     metadata: Dict = {}
     pier_correction: float = 0
-    scale_value:float = None
+    scale_value: float = None
 
     def __getitem__(self, measurement_type: MeasurementType):
         """Provide access to measurements by type.