code: def source_table(self):
          
          url = 'https://github.com/gammapy/gammapy-extra/raw/master/datasets/fermi_2fhl/gll_psch_v08.fit.gz'
          table = Table.read(url, hdu='2FHL Source Catalog')
          table.rename_column('Npred', 'COUNTS')
          table.keep_columns(['GLON', 'GLAT', 'COUNTS'])
          table.meta.clear()
          return table
docs: Source table  (`~astropy.table.Table`).
  
          Columns: GLON, GLAT, COUNTS