Error:  Data structure returned is not convertible in the requested format. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized. The data structure looks like this: 
 $data = array (
  0 => 
  array (
    0 => 
    array (
      0 => '2024-05-05',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    1 => 
    array (
      0 => '2024-05-06',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    2 => 
    array (
      0 => '2024-05-07',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    3 => 
    array (
      0 => '2024-05-08',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    4 => 
    array (
      0 => '2024-05-09',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    5 => 
    array (
      0 => '2024-05-10',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
    6 => 
    array (
      0 => '2024-05-11',
      1 => 
      array (
        'count' => 0,
        'starred' => 0,
      ),
    ),
  ),
);