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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 _parse_pod_segment(self, fptr):
 """Parse the POD segment. Parameters fptr : file Open file object. Returns ------- PODSegment The current POD segment. """

        offset = fptr.tell() - 2

        read_buffer = fptr.read(2)
        length, = struct.unpack('>H', read_buffer)

        n = ((length - 2) / 7) if self._csiz < 257 else ((length - 2) / 9)
        n = int(n)
        nbytes = n * 7 if self._csiz < 257 else n * 9
        read_buffer = fptr.read(nbytes)
        fmt = '>' + 'BBHBBB' * n if self._csiz < 257 else '>' + 'BHHBHB' * n
        pod_params = struct.unpack(fmt, read_buffer)

        return PODsegment(pod_params, length, offset)