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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 contains(self, key):
 """ Returns a boolean indicating if this node is responsible for handling the given key. """

        n = binascii.crc32(key.encode()) % RING_SIZE
        for start, end in self.ranges:
            if start <= n < end:
                return True
        return False