class FormatSizeEstimationSerializer ( serializers . Serializer ) :
    estimated_pbf_file_size_in_bytes = serializers . FloatField ( )
    detail_level = serializers . ChoiceField ( choices = detail_levels . DETAIL_LEVEL_CHOICES )
    def validate ( self , data ) :
        estimated_pbf = data [ "str" ]
        detail_level = data [ "str" ]
        data . update (
            {
                output_format : size_estimation_for_format ( output_format , detail_level , estimated_pbf )
                for output_format in output_format . DEFINITIONS
            }
        )
        return data
    def to_representation ( self , instance ) :
        instance

class FormatSizeEstimationSerializer ( serializers . Serializer ) :
    estimated_pbf_file_size_in_bytes = serializers . FloatField ( )
    detail_level = serializers . ChoiceField ( choices = detail_levels . DETAIL_LEVEL_CHOICES )
    def validate ( self , data ) :
        estimated_pbf = data [ "str" ]
        detail_level = data [ "str" ]
        data . update (
            {
                output_format : size_estimation_for_format ( output_format , detail_level , estimated_pbf )
                for output_format in output_format . DEFINITIONS
            }
        )
        return data
    def to_representation ( self , instance ) :
        return instance

次に示すpythonコードの誤りを修正しなさい。