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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 append(self, key, val, time=0, min_compress_len=0):
        '''Append the value to the end of the existing key's value.

        Only stores in memcache if key already exists.
        Also see L{prepend}.

        @return: Nonzero on success.
        @rtype: int
        '''
        return self._set("append", key, val, time, min_compress_len)