def METHOD_NAME(self, config=None):
    """
    Find and store paths to all config files.
    It searches for default configuration, files in XDG_CONFIG_DIRS and
    user defined configuration (argument "config"). All configuration
    file paths found are then stored in self.conf_files variable.
    XDG_CONFIG_DIRS contains preference-ordered set of base directories
    to search for configuration files. Users can override it by their
    own configuration file (config parameter) and then that is
    added too.
    """
    # first load up the file that contains defaults
    self.conf_files.append(self.config_defaults)
    # Skip auto-loading when running under PYTEST
    if not os.environ.get('PYTEST_XDIST_TESTRUNUID') and not os.environ.get('CONFIG_DISABLE_AUTOLOADING'):
        # Then load up config directories on system
        for directory in reversed(xdg_config_dirs):
            confdir = Path(directory) / 'rpmlint'
            if confdir.is_dir():
                # load all configs in the folders
                confopts = sorted(confdir.glob('*toml'))
                self.conf_files += confopts
    # As a last item load up the user configuration
    if config:
        for path in config:
            if path.exists():
                # load this only if it really exist
                self.conf_files.append(path)
            else:
                print_warning(f'(none): W: error locating user requested configuration: {path}')