public function deleteTasks($data = null) {
		if (empty($data) || !is_array($data)) {
			return false;
		}

		$excludeFields = [
			'data',
			'failure_message',
			'workerkey',
		];
		$data = array_diff_key($data, array_flip($excludeFields));
		$conditions = [];
		foreach ($data as $field => $value) {
			$conditions[$this->alias . '.' . $field] = $value;
		}

		if (empty($conditions)) {
			return false;
		}

		$countTasks = $this->find('count', compact('conditions'));
		if (($countTasks == 0) || !$this->deleteAll($conditions)) {
			return false;
		}

		return true;
	}