unable to convert string to date format with AM/PM
my sample code:
let dateFormatter = DateFormatter()
dateFormatter.dateFormat =  "yyyy-MM-dd HH:mm:ss.SSS"
if let todaysDate:Date = dateFormatter.date(from: dateString) {
    let newdateFormatter:DateFormatter = DateFormatter()
    newdateFormatter.dateFormat = "dd MMMM yyy hh:mm a"
    newdateFormatter.amSymbol = "AM"
    newdateFormatter.pmSymbol = "PM"
    return newdateFormatter.string(from: todaysDate)
}
input is: "2017-01-01 13:40:15.314"
output is: 01 January 2017 19:57
expected out put is: 01 January 2017 7:57 PM