public function addPostFields(array $formParams, array &$multipart, $arrayName = '')
{
foreach ($formParams as $name => $value) {
if (!empty($arrayName)) {
$name = $arrayName . '[' . $name . ']';
}
if (is_array($value)) {
$this->addPostFields($value, $multipart, $name);
} else {
$multipart[] = ['name' => $name, 'contents' => $value];
}
}
}