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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 hash64(key, seed):
 """ Wrapper around mmh3.hash64 to get us single 64-bit value. This also does the extra work of ensuring that we always treat the returned values as big-endian unsigned long, like smhasher used to do. """

    hash_val = mmh3.hash64(key, seed)[0]
    return struct.unpack('>Q', struct.pack('q', hash_val))[0]