Minor update

Author: marc-flex

tidy3d/components/data/data_array.py

@@ -1281,6 +1281,8 @@ class IndexedFieldDataArray(PointDataArray):
     >>> x_field = point_array.sel(axis=0)
     """
 
+    __slots__ = ()
+
 
 class IndexedFieldVoltageDataArray(DataArray):
     """Stores indexed values of vector fields for different voltages. It is typically used
@@ -1350,6 +1352,8 @@ class PerturbationCoefficientDataArray(DataArray):
     PointDataArray,
     CellDataArray,
     IndexedDataArray,
+    IndexedFieldDataArray,
+    IndexedFieldVoltageDataArray,
     IndexedVoltageDataArray,
     SpatialVoltageDataArray,
     PerturbationCoefficientDataArray,