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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 clear(cls, fn):
 # type: (FunctionType) -> None """ Clear result cache on the given function. If the function has no cached result, this call will do nothing. Args: fn (FunctionType):
 The function whose cache should be cleared. """

        if hasattr(fn, cls.CACHE_VAR):
            delattr(fn, cls.CACHE_VAR)