diff --git a/CAL/CalibrationCommon/lib/datacontainers/holography_dataset.py b/CAL/CalibrationCommon/lib/datacontainers/holography_dataset.py
index 20ba1e2623f5bf3a61487adae34b37b773e5d5af..7c6fe94e69d112814471df678e095eaec17d70b8 100644
--- a/CAL/CalibrationCommon/lib/datacontainers/holography_dataset.py
+++ b/CAL/CalibrationCommon/lib/datacontainers/holography_dataset.py
@@ -73,7 +73,7 @@ class HolographyDataset():
         self.calibration_tables = dict()
         self.derived_calibration_tables = dict()
         # coordinates of the antenna position in the target
-        self.antenna_field_position = []
+        self.antenna_field_position = list()
         # list of reference station names
         self.reference_stations = list()
         # list of _frequencies