code: def get_source(source):
      
      if source == 'gwtc-1':
          fname = download_file(gwtc1_url, cache=True)
          data = json.load(open(fname, 'r'))
      else:
          raise ValueError('Unkown catalog source {}'.format(source))
      return data['data']
docs: Get the source data for a particular GW catalog