GetUKCitizensImpertive.java

public List<String> getNamesOfUKCitizens(List<Person> persons)
{
  	List<String> allUKCitizens = new ArrayList<>();
  	for(Person p : persons)
	{
		if(p.getCitizenship() == Citizenship.UK){
			allUKCitizens.add(p.getName());
		}
	}
	return allUKCitizens;
}