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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(self, *resource_types):
 """Clear cache for each provided APIResource class, or all resources if no classes are provided"""

        resource_types = resource_types or tuple(self.__caches.keys())

        for cls in resource_types:
            # Clear and delete cache instances to guarantee no lingering references
            self.__caches[cls].clear()
            del self.__caches[cls]