replace lambda with method / class.method

gistfile1.cs

class Foo
{
  List<Person> _people = new List<Person>();
  IEnumerable<Person> Drinkers()
  {
    return people.Where(p => p.Age >= 18);
  }
  
  IEnumerable<Person> Drinkers2()
  {
    return people.Where(IsOfLegalDrinkingAge);
  }
  
  bool IsOfLegalDrinkingAge(Person person)
  {
    return person.Age >= 18;
  }
  
  
  IEnumerable<Person> Drinkers3()
  {
    var filter = _drinkingAgeService.GetFilterFor(Country.Australia);
    return people.Where(filter.IsAllowedToDrink)
  }
  
  class AustralianDrinkingAgeFilter
  {
    bool IsAllowedToDrink(Person person)
    {
      return person.Age >= 18;
    }
  }
  
  class RussionDrinkingAgeFilter
  {
    bool IsAllowedToDrink(Person person)
    {
      return true;
    }
  }
}