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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 decrypt(self, key, dev_addr):
 """ Decrypt the actual payload in this LoraPayload. key: 16-byte hex-encoded AES key. (i.e. AABBCCDDEEFFAABBCCDDEEFFAABBCCDD) dev_addr: 4-byte hex-encoded DevAddr (i.e. AABBCCDD) """

        sequence_counter = int(self.FCntUp)

        return loramac_decrypt(self.payload_hex, sequence_counter, key, dev_addr)