Is there any way to get some specific fields from a serializer to another serializer?

Question

I want all data from EmployeeLiteSerializer except designation data to BankInfoSerializer without detete get_designation_data method

 class EmployeeLiteSerializer(serializers.ModelSerializer):
        designation_data = serializers.SerializerMethodField(read_only=True)
    
        class Meta:
            model = Employee
            fields = ('first_name', 'last_name', 'code', 'designation_data')
    
        def get_designation_data(self, obj: Employee) -> Dict:
            try:
                return DesignationLiteSerializer(obj.designation).data
            except Designation.DoesNotExist:
                return {'message': 'No designation'}

    class BankInfoSerializer(serializers.ModelSerializer):
        employee = serializers.SerializerMethodField(read_only=True)
    
        class Meta:
            model = BankInfo
            fields = '__all__'
    
        def get_employee(self, obj: Employee) -> Dict:
            return EmployeeLiteSerializer(obj.employee).data

Answer 1

Use a new serializer for employee without designation_data .

# change the name to what you want
class BankInfoEmployeeSerializer(serializers.ModelSerializer):

    class Meta:
        model = Employee
        fields = ('first_name', 'last_name', 'code')


class BankInfoSerializer(serializers.ModelSerializer):
    employee = serializers.SerializerMethodField(read_only=True)

    class Meta:
        model = BankInfo
        fields = '__all__'

    def get_employee(self, obj: Employee) -> Dict:
        return BankInfoEmployeeSerializer(obj.employee).data

If employee is a field on BankInfo you can use it directly without SerializerMethodField

Answer 2

You can remove designation info:

class BankInfoSerializer(serializers.ModelSerializer):
    employee = serializers.SerializerMethodField(read_only=True)
    
    class Meta:
        model = BankInfo
        fields = '__all__'

    def get_employee(self, obj: Employee) -> Dict:
        employe_data = EmployeeLiteSerializer(obj.employee).data
        if 'designation_data' in employe_data:
            del employe_data['designation_data']
        
        return employe_data