code: def __netjson_channel_width(self, radio):
          
          htmode = radio.pop('htmode')
          if htmode == 'NONE':
              return 20
          channel_width = htmode.replace('VHT', '').replace('HT', '')
          # we need to override htmode
          if '+' in channel_width or '-' in channel_width:
              radio['htmode'] = htmode
              channel_width = channel_width[0:-1]
          return int(channel_width)
docs: determines NetJSON channel_width radio attribute