def validate_reaction(self):
if self.reaction not in self._reaction_valid_values:<EOL><INDENT>raise ValueError("<STR_LIT>".format(<EOL>valid="<STR_LIT:U+002CU+0020>".join(self._reaction_valid_values)<EOL>))<EOL><DEDENT>
Ensure reaction is of a certain type.

        Mainly for future expansion.