code: def config_function(self, token):
          
          match = token["match"]
          function = match.group(2).lower()
          param = match.group(3) or ""
          value_type = match.group(6) or "auto"
  
          # fix any escaped closing parenthesis
          param = param.replace(r"\)", ")")
  
          CONFIG_FUNCTIONS = {
              "base64": self.make_function_value_private,
              "env": self.make_value_from_env,
              "hide": self.make_function_value_private,
              "shell": self.make_value_from_shell,
          }
  
          return CONFIG_FUNCTIONS[function](param, value_type, function)
docs: Process a config function from a token