Returns the molar mixing ratio between the reactants with ORIGINAL (
        instead of processed) compositions for a reaction.

        Args:
            reaction (Reaction): Reaction object that contains the original
                reactant compositions.

        Returns:
            The molar mixing ratio between the original reactant
            compositions for a reaction.

def _get_original_composition_ratio(self, reaction):
        """
        Returns the molar mixing ratio between the reactants with ORIGINAL (
        instead of processed) compositions for a reaction.

        Args:
            reaction (Reaction): Reaction object that contains the original
                reactant compositions.

        Returns:
            The molar mixing ratio between the original reactant
            compositions for a reaction.
        """
        if self.c1_original == self.c2_original:
            return 1
        c1_coeff = reaction.get_coeff(self.c1_original) \
            if self.c1_original in reaction.reactants else 0
        c2_coeff = reaction.get_coeff(self.c2_original) \
            if self.c2_original in reaction.reactants else 0
        return c1_coeff * 1.0 / (c1_coeff + c2_coeff)