Getting the statistics with the default parameters...
object(stdClass)#5 (2) {
  ["Code"]=>
  int(100)
  ["Message"]=>
  string(15) "Invalid API Key"
}

Getting the statistics, filtered to a classic group...
object(stdClass)#7 (2) {
  ["Code"]=>
  int(100)
  ["Message"]=>
  string(15) "Invalid API Key"
}

Getting the statistics, filtered to a smart email...
object(stdClass)#6 (2) {
  ["Code"]=>
  int(100)
  ["Message"]=>
  string(15) "Invalid API Key"
}

Getting the most recent sent messages...