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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 _translate_src_oprnd(self, operand):
 """Translate source operand to a SMT expression. """

        if isinstance(operand, ReilRegisterOperand):
            return self._translate_src_register_oprnd(operand)
        elif isinstance(operand, ReilImmediateOperand):
            return smtsymbol.Constant(operand.size, operand.immediate)
        else:
            raise Exception("Invalid operand type")