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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 validate_reaction(self):
 """Ensure reaction is of a certain type. Mainly for future expansion. """

        if self.reaction not in self._reaction_valid_values:
            raise ValueError("reaction should be one of: {valid}".format(
                valid=", ".join(self._reaction_valid_values)
            ))