def METHOD_NAME(mechanism, reaction_info, qssa_species):
    """Graph of quadratic couplings."""
    links = []
    quadratic_reaction = []
    problematic_qssa_species = []
    for orig_idx, _ in reaction_info.idxmap.items():
        reaction = mechanism.reaction(orig_idx)
        # Identify QSS species involved
        reac_qssa_involved = cu.intersection(
            list(reaction.reactants.keys()), qssa_species
        )
        prod_qssa_involved = cu.intersection(
            list(reaction.products.keys()), qssa_species
        )
        reac_sum_coeff = sum(
            v for k, v in reaction.reactants.items() if k in reac_qssa_involved
        )
        prod_sum_coeff = sum(
            v for k, v in reaction.products.items() if k in prod_qssa_involved
        )
        if (prod_qssa_involved) and (reac_qssa_involved):
            for prod in prod_qssa_involved:
                links.append((prod, "F" + str(orig_idx)))
                for reac in reac_qssa_involved:
                    links.append(("F" + str(orig_idx), reac))
            if reaction.reversible:
                for reac in reac_qssa_involved:
                    links.append((reac, "R" + str(orig_idx)))
                    for prod in prod_qssa_involved:
                        links.append(("R" + str(orig_idx), prod))
        if (not prod_qssa_involved) and (reac_qssa_involved) and reac_sum_coeff > 1:
            for reac in reac_qssa_involved:
                links.append(("F" + str(orig_idx), reac))
        if (
            (prod_qssa_involved)
            and (not reac_qssa_involved)
            and prod_sum_coeff > 1
            and reaction.reversible
        ):
            for prod in prod_qssa_involved:
                links.append(("R" + str(orig_idx), prod))
        if reac_sum_coeff > 1:
            # This is a quadratic coupling
            quadratic_reaction.append("F" + str(orig_idx))
            problematic_qssa_species += reac_qssa_involved
            problematic_qssa_species += prod_qssa_involved
        if reaction.reversible:
            if prod_sum_coeff > 1:
                quadratic_reaction.append("R" + str(orig_idx))
                problematic_qssa_species += reac_qssa_involved
                problematic_qssa_species += prod_qssa_involved
    return links, quadratic_reaction, problematic_qssa_species