Trello Webhook - Missing data

blog-2015-10-21-TrelloWebhook8.php

<?php
    } else {
      // DATA LOOKS NOT GOOD, NOTE IN CARD
      $msg = '';
      if (!$account_id) $msg .= 'Invalid account selected' . "\n\n";
      if (!is_numeric($amt)) $msg .= 'Invalid amount selected: ' . $amt . "\n\n";
      if (!$category) $msg .= 'No category found' . "\n\n";

      if ($msg) $trello->request('POST', ('/1/card/' . $data->model->id . '/actions/comments'), array('text' => trim($msg)));
    }
  }