old_contents: #!/usr/bin/env python
  # Developer virtualenv setup for Certbot client
  import _venv_common
  
  REQUIREMENTS = [
      '-e acme[dev]',
      '-e .[dev,docs]',
      '-e certbot-apache',
      '-e certbot-dns-cloudflare',
      '-e certbot-dns-cloudxns',
      '-e certbot-dns-digitalocean',
      '-e certbot-dns-dnsimple',
      '-e certbot-dns-dnsmadeeasy',
      '-e certbot-dns-gehirn',
      '-e certbot-dns-google',
      '-e certbot-dns-linode',
      '-e certbot-dns-luadns',
      '-e certbot-dns-nsone',
      '-e certbot-dns-ovh',
      '-e certbot-dns-rfc2136',
      '-e certbot-dns-route53',
      '-e certbot-dns-sakuracloud',
      '-e certbot-nginx',
      '-e certbot-postfix',
      '-e letshelp-certbot',
      '-e certbot-compatibility-test',
  ]
  
  
  def main():
      venv_args = '--python "{0}"'.format(_venv_common.find_python_executable(3))
      _venv_common.main('venv3', venv_args, REQUIREMENTS)
  
  
  if __name__ == '__main__':
      main()
  
new_contents: #!/usr/bin/env python3
  # Developer virtualenv setup for Certbot client
  import _venv_common
  
  REQUIREMENTS = [
      '-e acme[dev]',
      '-e .[dev,docs]',
      '-e certbot-apache',
      '-e certbot-dns-cloudflare',
      '-e certbot-dns-cloudxns',
      '-e certbot-dns-digitalocean',
      '-e certbot-dns-dnsimple',
      '-e certbot-dns-dnsmadeeasy',
      '-e certbot-dns-gehirn',
      '-e certbot-dns-google',
      '-e certbot-dns-linode',
      '-e certbot-dns-luadns',
      '-e certbot-dns-nsone',
      '-e certbot-dns-ovh',
      '-e certbot-dns-rfc2136',
      '-e certbot-dns-route53',
      '-e certbot-dns-sakuracloud',
      '-e certbot-nginx',
      '-e certbot-postfix',
      '-e letshelp-certbot',
      '-e certbot-compatibility-test',
  ]
  
  
  def main():
      venv_args = '--python "{0}"'.format(_venv_common.find_python_executable(3))
      _venv_common.main('venv3', venv_args, REQUIREMENTS)
  
  
  if __name__ == '__main__':
      main()
  
subject: Use Python3 to run tools/venv3.py. (#6860)