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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 export(self, chunk_size=DEFAULT_DATA_CHUNK_SIZE):
 """ Export the contents of the container's filesystem as a tar archive. Args: chunk_size (int):
 The number of bytes returned by each iteration of the generator. If ``None``, data will be streamed as it is received. Default: 2 MB Returns: (str):
 The filesystem tar archive Raises: :py:class:`docker.errors.APIError` If the server returns an error. """

        return self.client.api.export(self.id, chunk_size)