Set a namespace in dropdown in google sheet

 function setDropdownUsingNamedRange() {

  var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();

  var range = sheet.getRange("C3"); // Change this to the cell where you want the dropdown

 

  // Set the named range as the source for the dropdown

  var rule = SpreadsheetApp.newDataValidation()

              .requireValueInRange(SpreadsheetApp.getActiveSpreadsheet().getRangeByName("Caps"), true)

              .build();

             

  range.setDataValidation(rule);

}