Shortcut to get Inbox Folder instance

        :rtype: mailbox.Folder

def inbox_folder(self):
        """ Shortcut to get Inbox Folder instance

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