Shortcut to get SentItems Folder instance

        :rtype: mailbox.Folder

def sent_folder(self):
        """ Shortcut to get SentItems Folder instance

        :rtype: mailbox.Folder
        """
        return self.folder_constructor(parent=self, name='SentItems',
                                       folder_id=OutlookWellKnowFolderNames
                                       .SENT.value)