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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 SignMessage(self, message, script_hash):
 """ Sign a message with a specified script_hash. Args: message (str):
 a hex encoded message to sign script_hash (UInt160):
 a bytearray (len 20). Returns: str: the signed message """


        keypair = self.GetKeyByScriptHash(script_hash)
        prikey = bytes(keypair.PrivateKey)
        res = Crypto.Default().Sign(message, prikey)
        return res, keypair.PublicKey