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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 close(self):
 """ Disable al operations and close the underlying file-like object, if any """

        if callable(getattr(self._file, 'close', None)):
            self._iterator.close()
        self._iterator = None
        self._unconsumed = None
        self.closed = True