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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 _get_default_jp2_boxes(self):
 """Create a default set of JP2 boxes."""

        # Try to create a reasonable default.
        boxes = [JPEG2000SignatureBox(),
                 FileTypeBox(),
                 JP2HeaderBox(),
                 ContiguousCodestreamBox()]
        height = self.codestream.segment[1].ysiz
        width = self.codestream.segment[1].xsiz
        num_components = len(self.codestream.segment[1].xrsiz)
        if num_components < 3:
            colorspace = core.GREYSCALE
        else:
            if len(self.box) == 0:
                # Best guess is SRGB
                colorspace = core.SRGB
            else:
                # Take whatever the first jp2 header / color specification
                # says.
                jp2hs = [box for box in self.box if box.box_id == 'jp2h']
                colorspace = jp2hs[0].box[1].colorspace

        boxes[2].box = [ImageHeaderBox(height=height, width=width,
                                       num_components=num_components),
                        ColourSpecificationBox(colorspace=colorspace)]

        return boxes