def expand_files(self, modules):
        """get modules and errors from a list of modules and handle errors
        """
        result, errors = utils.expand_modules(
            modules, self.config.black_list, self.config.black_list_re
        )
        for error in errors:
            message = modname = error["mod"]
            key = error["key"]
            self.set_current_module(modname)
            if key == "fatal":
                message = str(error["ex"]).replace(os.getcwd() + os.sep, "")
            self.add_message(key, args=message)
        return result
get modules and errors from a list of modules and handle errors