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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_parent_folder(self):
 """ Get the parent folder from attribute self.parent or getting it from the cloud :return: Parent Folder :rtype: mailbox.Folder or None """

        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