def generate_migration_name(self, name, suffix):
return os.path.join(self.dir,<EOL>'<STR_LIT>'.format(<EOL>datestr=datetime.datetime.utcnow().strftime('<STR_LIT>'),<EOL>name=name.replace('<STR_LIT:U+0020>', '<STR_LIT:_>'),<EOL>suffix=suffix))<EOL>
Returns a name of a new migration. It will usually be a filename with
        a valid and unique name.

        :param name: human-readable name of a migration
        :param suffix: file suffix (extension) - eg. 'sql'