def read(self):
        """Read the default, additional, system, and user config files.

        :raises DefaultConfigValidationError: There was a validation error with
                                              the *default* file.
        """
        if self.default_file:
            self.read_default_config()
        return self.read_config_files(self.all_config_files())
Read the default, additional, system, and user config files.

        :raises DefaultConfigValidationError: There was a validation error with
                                              the *default* file.