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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 _lookup(self, skip_cache, fun, *args, **kwargs):
 """ Checks for cached responses, before requesting from web-service """

        if args not in self.cache or skip_cache:
            self.cache[args] = fun(*args, **kwargs)
        return self.cache[args]