how to download office 365 mail attachment file using laravel

I'm using Microsoft graph API for fetching office 365 mails. I got all email from API call. but I don't know how to save an attachment from the message object. how to save contentBytes to file

Microsoft\Graph\Model\Message Object
(
  [_propDict:protected] => Array
  (
    [@odata.context] => https://graph.microsoft.com/v1.0/$metada
    [@odata.type] => #microsoft.graph.fileAttachment
    [@odata.mediaContentType] => application/pdf
    [id] => AAMkADM4MDYwMDkxLWRmN2UtNDJmMC04NDEwLTljZmQ2N2I4Zjc5NABGAAAAAAAix7kDZj2fRq
    [lastModifiedDateTime] => 2016-04-18T09:44:53Z
    [name] => 1 ) Muhammad Abdullah New.pdf
    [contentType] => application/pdf
    [size] => 104767
    isInline] =>
    [contentId] => C#$F3@eurprd06.prod.outlook.com
    [contentLocation] => 
    [contentBytes] => JVBERi0xLjUNJeLjz9MNyuFJFtfTffYSTIgCjUwNSAwIG9iag08PC9MaW
  )
)

via Chebli Mohamed