... class, and those that have thesame lifetime. Once we’ve found a coincidence, we have the harder task of findinga good name that explains the concept.As an aside, one sign that a design is developing ... playRadio(Frequency frequency) { tuner.tuneTo(frequency); tuner.play(); }// and so on}Like our mobile phones, this class has several unrelated responsibilities whichforce it to pull in many dependencies. ... that should betaken down once the job is done, or essential infrastructure that should be testedand maintained? That depends on the system, but once we’ve made the distinctionwe have more freedom...