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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 crypto_sign(msg, sk):
 """Return signature+message given message and secret key. The signature is the first SIGNATUREBYTES bytes of the return value. A copy of msg is in the remainder."""

    if len(sk) != SECRETKEYBYTES:
        raise ValueError("Bad signing key length %d" % len(sk))
    vkbytes = sk[PUBLICKEYBYTES:]
    skbytes = sk[:PUBLICKEYBYTES]
    sig = djbec.signature(msg, skbytes, vkbytes)
    return sig + msg