<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def best(cls):
 """ Select the best ScriptWriter suitable for Windows """

        writer_lookup = dict(
            executable=WindowsExecutableLauncherWriter,
            natural=cls,
        )
        # for compatibility, use the executable launcher by default
        launcher = os.environ.get('SETUPTOOLS_LAUNCHER', 'executable')
        return writer_lookup[launcher]