code: def get_parent_folder(self):
          
          if self.root:
              return None
          if self.parent:
              return self.parent
  
          if self.parent_id:
              self.parent = self.get_folder(folder_id=self.parent_id)
          return self.parent
docs: Get the parent folder from attribute self.parent or
          getting it from the cloud
  
          :return: Parent Folder
          :rtype: mailbox.Folder or None