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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 using_config(_func=None):
 """ This allows a function to use Summernote configuration as a global variable, temporarily. """

    def decorator(func):
        @wraps(func)
        def inner_dec(*args, **kwargs):
            g = func.__globals__
            var_name = 'config'
            sentinel = object()

            oldvalue = g.get(var_name, sentinel)
            g[var_name] = apps.get_app_config('django_summernote').config

            try:
                res = func(*args, **kwargs)
            finally:
                if oldvalue is sentinel:
                    del g[var_name]
                else:
                    g[var_name] = oldvalue

            return res
        return inner_dec

    if _func is None:
        return decorator
    else:
        return decorator(_func)