old_contents: """nginx plugin constants."""
  import pkg_resources
  
  
  CLI_DEFAULTS = dict(
      server_root="/etc/nginx",
      ctl="nginx",
  )
  """CLI defaults."""
  
  
  MOD_SSL_CONF_DEST = "options-ssl-nginx.conf"
  """Name of the mod_ssl config file as saved in `IConfig.config_dir`."""
  
  MOD_SSL_CONF_SRC = pkg_resources.resource_filename(
      "certbot_nginx", "options-ssl-nginx.conf")
  """Path to the nginx mod_ssl config file found in the Certbot
  distribution."""
  
  def os_constant(key):
      # XXX TODO: In the future, this could return different constants
      #           based on what OS we are running under.  To see an
      #           approach to how to handle different OSes, see the
      #           apache version of this file.
      return CLI_DEFAULTS[key]
  
new_contents: """nginx plugin constants."""
  import pkg_resources
  
  
  CLI_DEFAULTS = dict(
      server_root="/etc/nginx",
      ctl="nginx",
  )
  """CLI defaults."""
  
  
  MOD_SSL_CONF_DEST = "options-ssl-nginx.conf"
  """Name of the mod_ssl config file as saved in `IConfig.config_dir`."""
  
  MOD_SSL_CONF_SRC = pkg_resources.resource_filename(
      "certbot_nginx", "options-ssl-nginx.conf")
  """Path to the nginx mod_ssl config file found in the Certbot
  distribution."""
  
  def os_constant(key):
      # XXX TODO: In the future, this could return different constants
      #           based on what OS we are running under.  To see an
      #           approach to how to handle different OSes, see the
      #           apache version of this file.  Currently, we do not
      #           actually have any OS-specific constants on Nginx.
      """
      Get a constant value for operating system
  
      :param key: name of cli constant
      :return: value of constant for active os
      """
      return CLI_DEFAULTS[key]
  
subject: Add function docstring