docs: def populate(dataset_name, data_web_service_url=DATA_WEB_SERVICE + "CFHT"):
      """Given a dataset_name created the desired dbimages directories
      and links to the raw data files stored at CADC.
      @param dataset_name: the name of the CFHT dataset to make a link to.
      @param data_web_servica_url: the URL of the data web service run by CADC.
      """
  
      data_dest = get_uri(dataset_name, version='o', ext=FITS_EXT)
      data_source = "%s/%so.{}" % (data_web_service_url, dataset_name, FITS_EXT)
  
      mkdir(os.path.dirname(data_dest))
  
      try:
          client.link(data_source, data_dest)
      except IOError as e:
          if e.errno == errno.EEXIST:
              pass
          else:
              raise e
  
      header_dest = get_uri(dataset_name, version='o', ext='head')
      header_source = "%s/%so.fits.fz?cutout=[0]" % (
          data_web_service_url, dataset_name)
      try:
          client.link(header_source, header_dest)
      except IOError as e:
          if e.errno == errno.EEXIST:
              pass
          else:
              raise e
  
      header_dest = get_uri(dataset_name, version='p', ext='head')
      header_source = "%s/%s/%sp.head" % (
          'http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/data/pub', 'CFHTSG', dataset_name)
      try:
          client.link(header_source, header_dest)
      except IOError as e:
          if e.errno == errno.EEXIST:
              pass
          else:
              raise e
  
      return True