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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 _write_superbox(self, fptr, box_id):
 """Write a superbox. Parameters fptr : file or file object Superbox (box of boxes) to be written to this file. box_id : bytes 4-byte sequence that identifies the superbox. """

        # Write the contained boxes, then come back and write the length.
        orig_pos = fptr.tell()
        fptr.write(struct.pack('>I4s', 0, box_id))
        for box in self.box:
            box.write(fptr)

        end_pos = fptr.tell()
        fptr.seek(orig_pos)
        fptr.write(struct.pack('>I', end_pos - orig_pos))
        fptr.seek(end_pos)