code: def _parse_crg_segment(self, fptr):
          
          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)
docs: Parse the CRG marker segment.
  
          Parameters
          ----------
          fptr : file
              Open file object.
  
          Returns
          -------
          CRGSegment
              The current CRG segment.