Produce an EXCHANGE instruction.

    :param classical_reg1: The first classical register, which gets modified.
    :param classical_reg2: The second classical register, which gets modified.
    :return: A ClassicalExchange instance.

def EXCHANGE(classical_reg1, classical_reg2):
    """
    Produce an EXCHANGE instruction.

    :param classical_reg1: The first classical register, which gets modified.
    :param classical_reg2: The second classical register, which gets modified.
    :return: A ClassicalExchange instance.
    """
    left = unpack_classical_reg(classical_reg1)
    right = unpack_classical_reg(classical_reg2)
    return ClassicalExchange(left, right)