docs: def get_apcor(expnum, ccd, version='p', prefix=None):
      """
      retrieve the aperture correction for this exposure
      @param expnum:
      @param ccd:
      @param version:
      @param prefix:
      @return:
      """
      uri = get_uri(expnum, ccd, ext=APCOR_EXT, version=version, prefix=prefix)
      apcor_file_name = tempfile.NamedTemporaryFile()
      client.copy(uri, apcor_file_name.name)
      apcor_file_name.seek(0)
      return [float(x) for x in apcor_file_name.readline().split()]