Google Spreadsheet AppScript that publishes JSON of a Sum

gistfile1.js

function getTickets() {
 var sheet = SpreadsheetApp.openById("SPREADSHEET_ID").getSheetByName("SHEET_NAME_WITH_SUM");
 var count = sheet.getRange("LOCATION_OF_CELL");
 return count.getValue();
}


function doGet() {
  var result = {
    "TITLE_OF_SUM":this.getTickets()
  }
  return ContentService.createTextOutput(JSON.stringify(result)).setMimeType(ContentService.MimeType.JSON);
}