Why does this c# code has two angular bracket '>>' after IHeapifyable in this line

Question

The method is in a class Heap which creates a Heap data structure in C# This method finds the Kth minimum value in O(K log n) time What does this line exactly do

List<IHeapifyable<K, D>> temp = new List<IHeapifyable<K, D>>();

Can someone explain this specific line in a C# code The whole code is over here

public IHeapifyable<K, D> KthMinElement(int k)
    {
        if (Count is 0) throw new InvalidOperationException();
        if (k <= 0 || k > Count) throw new ArgumentOutOfRangeException();

        IHeapifyable<K, D> kthMin = null;
        List<IHeapifyable<K, D>> temp = new List<IHeapifyable<K, D>>();
        for (int i = 1; i <= k; i++)
        {
            if (i == k) kthMin = data[1];
            temp.Add(this.Delete());
        }
        foreach (var node in temp) this.Insert(node.Key, node.Data);

        return kthMin;
    }

Answer 1

The angle brackets are the opening and closing of what is contained in the data type they are describing.

List<IHeapifyable<K, D>> temp = new List<IHeapifyable<K, D>>();

So what this line says is: Create a List data type containing one or more IHeapifyable<K,D> data types and assign it to the variable temp

A List of integers is initialized with this

List<int>

Your example is the same except instead of int it's

IHeaplifyable<K,D>

so if you replace the int with IHeaplifyable you get.

List<IHeaplifyable<K,D>>

Answer 2

The angle brackets are enclosing the generic type parameters. It's using a List<T> where T is IHeapifyable<K, D>, so it's a List<IHeapifyable<K, D>>. It's just like if you were to nest method calls like this:

Method1(Method2(arg));

so you end up with two closing parentheses at the end.