docs: def pull_env_credential(env, param, value):
      """
      Dissects a keyring credential lookup string from the supernova config file
      and returns the username/password combo
      """
      rex = "USE_KEYRING\[([\x27\x22])(.*)\\1\]"
  
      # This is the old-style, per-environment keyring credential
      if value == "USE_KEYRING":
          username = utils.assemble_username(env, param)
  
      # This is the new-style, global keyring credential that can be applied
      # to multiple environments
      else:
          global_identifier = re.match(rex, value).group(2)
          username = utils.assemble_username('global', global_identifier)
  
      return (username, password_get(username))