code: def vstack_tables(filelist, hdus):
      
      nfiles = len(filelist)
      out_tables = []
      out_names = []
      for hdu in hdus:
          sys.stdout.write('Working on %i files for %s: ' % (nfiles, hdu))
          sys.stdout.flush()
          tlist = []
          for f in filelist:
              try:
                  tab = Table.read(f, hdu)
                  tlist.append(tab)
                  sys.stdout.write('.')
              except KeyError:
                  sys.stdout.write('x')
              sys.stdout.flush()
          sys.stdout.write('!\n')
          if tlist:
              out_table = vstack(tlist)
              out_tables.append(out_table)
              out_names.append(hdu)
      return (out_tables, out_names)
docs: vstack a set of HDUs from a set of files
  
      Parameters
      ----------
  
      filelist : list
          List of the files to get data from.
  
      hdus : list
          Names of the HDU containing the table with the input data.
  
      Returns
      -------
  
      out_tables : list
          A list with the table with all the requested data extracted.
  
      out_names : list
          A list with the names of the tables.