using System;
using System.Collections.Generic;
 
class Program {
    static void Main() {
        Console.WriteLine(HasItem(new List<string>(), null));
        try {
        	Console.WriteLine(HasItem(new SortedList<string, int>().Keys, null));
    	} catch (ArgumentNullException) {
        	Console.WriteLine("ArgumentNullException");
    	}
    }
 
    public static bool HasItem(ICollection<string> collection, string item) {
        return collection.Contains(item);
    }
}

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