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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_crg_segment(self, fptr):
 """Parse the CRG marker segment. Parameters fptr : file Open file object. Returns ------- CRGSegment The current CRG segment. """

        offset = fptr.tell() - 2

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

        read_buffer = fptr.read(4 * self._csiz)
        data = struct.unpack('>' + 'HH' * self._csiz, read_buffer)
        xcrg = data[0::2]
        ycrg = data[1::2]

        return CRGsegment(xcrg, ycrg, length, offset)