if ($operation === null) {
     throw new Exception("Call to pruebaFunctions without 'Operation' requested");
 }
 $pruebaID = http_request("ID", "i", 0);
 switch ($operation) {
     case "insert":
         $am->access(PERMS_OPERATOR);
         $result = $pruebas->insert();
         break;
     case "update":
         $am->access(PERMS_OPERATOR);
         $result = $pruebas->update($pruebaID);
         break;
     case "delete":
         $am->access(PERMS_OPERATOR);
         $result = $pruebas->delete($pruebaID);
         break;
     case "select":
         $result = $pruebas->select();
         break;
     case "enumerate":
         $result = $pruebas->enumerate($am);
         break;
     case "getbyid":
         $result = $pruebas->selectByID($pruebaID);
         break;
     default:
         throw new Exception("pruebaFunctions:: invalid operation: {$operation} provided");
 }
 if ($result === null) {
     throw new Exception($pruebas->errormsg);