def create_new_python_version(self, description, **k):
        """Create Python files for new version"""
        ver = self._next_ver_num(k.pop('use_timestamp_numbering', False))
        extra = str_to_filename(description)

        if extra:
            if extra == '_':
                extra = ''
            elif not extra.startswith('_'):
                extra = '_%s' % extra

        filename = '%03d%s.py' % (ver, extra)
        filepath = self._version_path(filename)

        script.PythonScript.create(filepath, **k)
        self.versions[ver] = Version(ver, self.path, [filename])