def multiply_rxn(value, reaction):
    """
    A stoichiometric reaction A -> B + 2C can be multiplied by x leading to xA -> xB + 2xC
    :param value: Multiplier
    :param reaction:  Cobra reaction object

    """

    mr = reaction.copy()
    mr_mets = mr.metabolites
    mr.subtract_metabolites(mr_mets)
    new_mets = {met: value*coeff for met, coeff in mr_mets.items()}
    mr.add_metabolites(new_mets)
    return mr