private static void mergeInto(Map<String, Phase> resultingPhases, Map<String, Phase> phases) {
        for (Phase phase : phases.values()) {
            String name = phase.getName();
            if (resultingPhases.containsKey(name)) {
                phase = phase.union(resultingPhases.get(name));
            }
            resultingPhases.put(name, phase);
        }
    }
@param allChainSpecifications resolves ChainSpecifications from ComponentSpecifications
                              as given in the inheritance fields.
@param path tracks which chains are used in each recursive invocation of flatten, used for detecting cycles.
@return ChainSpecification directly containing all the component references and phases of the inherited chains.
container-core/src/main/java/com/yahoo/component/chain/model/ChainSpecification.java