using System;

using System.Collections.Generic;

using System.Linq;

​

public class Animal 

{

    public string Name { get; set; }

}

public class Cat : Animal { }

public class Dog : Animal { }

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(GetFilteredAnimals("Pe", GetCats));

    }

    private static List<Cat> GetCats()

    {

        return new List<Cat>() { new Cat { Name = "Sphinx" }, new Cat { Name = "Persian" } };

    }

    private static List<Dog> GetDogs()

    {

        return new List<Dog>() { new Dog { Name = "Bulldog"}, new Dog { Name = "Dalmatian" } };

    }

    private static List<Animal> GetFilteredAnimals(string f, Func<List<Animal>> method)

    {

        var animals = method();

        return animals.Where(a => a.Name.StartsWith(f)).ToList<Animal>();

    }

}