public abstract class ImmutableAvlTreeBase<TKey, TValue> : IEnumerable<IKeyValuePair<TKey, TValue>>, 
	IEnumerable
where TKey : Object, IComparable<TKey>

Public MustInherit Class ImmutableAvlTreeBase(Of TKey As {Object, IComparable(Of TKey)}, TValue)
	Implements IEnumerable(Of IKeyValuePair(Of TKey, TValue)), 
	IEnumerable

generic<typename TKey, typename TValue>
where TKey : Object, IComparable<TKey>
public ref class ImmutableAvlTreeBase abstract : IEnumerable<IKeyValuePair<TKey, TValue>^>, 
	IEnumerable

[<AbstractClassAttribute>]
type ImmutableAvlTreeBase<'TKey, 'TValue when 'TKey : Object and IComparable<'TKey>> =  
    class
        interface IEnumerable<IKeyValuePair<'TKey, 'TValue>>
        interface IEnumerable
    end