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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 _fast_memory_load_pointer(self, addr, size=None):
 """ Perform a fast memory loading of a pointer. :param int addr: Address to read from. :param int size: Size of the pointer. Default to machine-word size. :return: A pointer or None if the address does not exist. :rtype: int """


        try:
            return self.project.loader.memory.unpack_word(addr, size=size)
        except KeyError:
            return None