code: def proxy_bypass_environment(host):
      
      no_proxy = os.environ.get('no_proxy', '') or os.environ.get('NO_PROXY', '')
      # '*' is special case for always bypass
      if no_proxy == '*':
          return 1
      # strip port off host
      hostonly, port = splitport(host)
      # check if the host ends with any of the DNS suffixes
      no_proxy_list = [proxy.strip() for proxy in no_proxy.split(',')]
      for name in no_proxy_list:
          if name and (hostonly.endswith(name) or host.endswith(name)):
              return 1
      # otherwise, don't bypass
      return 0
docs: Test if proxies should not be used for a particular host.
  
      Checks the environment for a variable named no_proxy, which should
      be a list of DNS suffixes separated by commas, or '*' for all hosts.