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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def DefaultEnvironment(*args, **kw):
 """ Initial public entry point for creating the default construction Environment. After creating the environment, we overwrite our name (DefaultEnvironment) with the _fetch_DefaultEnvironment() function, which more efficiently returns the initialized default construction environment without checking for its existence. (This function still exists with its _default_check because someone else (*cough* Script/__init__.py *cough*) may keep a reference to this function. So we can't use the fully functional idiom of having the name originally be a something that *only* creates the construction environment and then overwrites the name.) """

    global _default_env
    if not _default_env:
        import SCons.Util
        _default_env = SCons.Environment.Environment(*args, **kw)
        if SCons.Util.md5:
            _default_env.Decider('MD5')
        else:
            _default_env.Decider('timestamp-match')
        global DefaultEnvironment
        DefaultEnvironment = _fetch_DefaultEnvironment
        _default_env._CacheDir_path = None
    return _default_env