var chart4 = sheet.newChart()
.setChartType(Charts.ChartType.LINE)
.addRange(sheet.getRange("A1:G100"))
.setOption('title','Page and Session RPM by Site')
.setOption('aggregationTarget', 'category')
.setOption('legend',{position:'bottom'})
.setPosition(1, 1, 0, 0)
.build();
But by default, it doesn't check the "Use row 1 as headers" option, how can I set this using google script?