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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 eval(self, x):
 """This method returns the evaluation of the function with input x :param x: this is the input as a Long """

        aes = AES.new(self.key, AES.MODE_CFB, "\0" * AES.block_size)
        while True:
            nonce = 0
            data = KeyedPRF.pad(SHA256.new(str(x + nonce).encode()).digest(),
                                (number.size(self.range) + 7) // 8)
            num = self.mask & number.bytes_to_long(aes.encrypt(data))
            if (num < self.range):
                return num
            nonce += 1