code: async def save(proxies, filename):
      
      with open(filename, 'w') as f:
          while True:
              proxy = await proxies.get()
              if proxy is None:
                  break
              proto = 'https' if 'HTTPS' in proxy.types else 'http'
              row = '%s://%s:%d\n' % (proto, proxy.host, proxy.port)
              f.write(row)
docs: Save proxies to a file.