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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 load_hdu(self, imname, hdulist, num_hdu):
 """Display an astropy.io.fits HDU in a remote Ginga reference viewer. Parameters imname : str A name to use for the image in the reference viewer. hdulist : `~astropy.io.fits.HDUList` This should be a valid HDUList loaded via the `astropy.io.fits` module. num_hdu : int or 2-tuple Number or key of the HDU to open from the `HDUList`. Returns ------- 0 Notes ----- * The "RC" plugin needs to be started in the viewer for this to work. """

        buf_io = BytesIO()
        hdulist.writeto(buf_io)

        load_fits_buffer = self._client.lookup_attr('load_fits_buffer')

        return load_fits_buffer(imname, self._chname,
                                Blob(buf_io.getvalue()),
                                num_hdu, {})