protected function prepareSaveData($fieldPrefix, $fieldsConfig)
	{
		foreach ($fieldsConfig as $fieldName => $fieldConfig) {

			if (isset($fieldConfig['inputType']) && $fieldConfig['inputType'] === 'list') {

				// creates an empty array for a empty lists
				$fieldData = $this->getNestedValueReference($fieldPrefix . $fieldName);

				for ($dataKey = 0; isset($fieldData[$dataKey]); $dataKey++) {
					$this->prepareSaveData($fieldPrefix . $fieldName . '__' . $dataKey . '__', $fieldConfig['fields']);
				}

			}

		}
	}