How to use the druid-query-toolkit.ComparisonExpressionRhs function in druid-query-toolkit

onQueryChange(
              parsedQuery.addAggregateColumn(
                refExpressionFactory('*'),
                'COUNT',
                aliasFactory(`${columnName}_filtered_count`),
                false,
                new FilterClause({
                  keyword: 'FILTER',
                  spacing: [' '],
                  ex: new WhereClause({
                    keyword: 'WHERE',
                    spacing: [' '],
                    filter: new ComparisonExpression({
                      parens: [],
                      ex: stringFactory(columnName, '"'),
                      rhs: new ComparisonExpressionRhs({
                        parens: [],
                        op: '=',
                        rhs: stringFactory('xxx', `'`),
                        spacing: [' ', ' '],
                      }),
                    }),
                  }),
                }),
              ),
            );
          }}
        />