using System;

using System.Runtime.CompilerServices;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    static List<Person> persons = new List<Person>() {

        new Person(1, "Person1", "Chennai"),

        new Person(2, "Person2", "Mumbai"),

        new Person(3, "Person3", "Delhi"),

    };

    public static void Main()

    {

        var a = 5;

        CheckExpression(a > 5);

        FilterPersons(p => p.City == "Bangalore");

    }

    static void CheckExpression(bool condition, [CallerArgumentExpression("condition")] string message = null)

    {

        if(condition) {

            Console.WriteLine("continue success");

        }

        else

        {

            Console.WriteLine($"Condition failed - {message}");

        }

    }

    static List<Person> FilterPersons(Func<Person, bool> condition,  [CallerArgumentExpression("condition")] string message = null) {

        var result = persons.Where(condition);

        if(result.Count() == 0) {

            Console.WriteLine($"filter 0 records - {message}");

        }

        return result.ToList();

    }

}

​

public record Person(int Id, string FirstName, string City);