array(3) {
  ["a"]=>
  string(1) "1"
  [2]=>
  int(2)
  ["c"]=>
  string(1) "3"
}
array(4) {
  ["a"]=>
  string(1) "1"
  [2]=>
  int(2)
  ["c"]=>
  string(1) "3"
  ["d"]=>
  array(3) {
    ["a"]=>
    string(1) "1"
    [2]=>
    int(2)
    ["c"]=>
    string(1) "3"
  }
}