diff --git a/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_serialization.py b/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_serialization.py
index eb86ea23c965..6ae41e09f4a9 100644
--- a/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_serialization.py
+++ b/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_serialization.py
@@ -789,7 +789,7 @@ def serialize_data(self, data, data_type, **kwargs):
 
             # If dependencies is empty, try with current data class
             # It has to be a subclass of Enum anyway
-            enum_type = self.dependencies.get(data_type, data.__class__)
+            enum_type = self.dependencies.get(data_type, cast(type, data.__class__))
             if issubclass(enum_type, Enum):
                 return Serializer.serialize_enum(data, enum_obj=enum_type)
 
diff --git a/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_utils/serialization.py b/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_utils/serialization.py
index eb86ea23c965..6ae41e09f4a9 100644
--- a/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_utils/serialization.py
+++ b/sdk/healthdataaiservices/azure-health-deidentification/azure/health/deidentification/_utils/serialization.py
@@ -789,7 +789,7 @@ def serialize_data(self, data, data_type, **kwargs):
 
             # If dependencies is empty, try with current data class
             # It has to be a subclass of Enum anyway
-            enum_type = self.dependencies.get(data_type, data.__class__)
+            enum_type = self.dependencies.get(data_type, cast(type, data.__class__))
             if issubclass(enum_type, Enum):
                 return Serializer.serialize_enum(data, enum_obj=enum_type)