public static PipelineDefinition<TInput, BsonDocument> GraphLookup<TInput, TIntermediate, TFrom>(
	this PipelineDefinition<TInput, TIntermediate> pipeline,
	IMongoCollection<TFrom> from,
	FieldDefinition<TFrom, BsonValue> connectFromField,
	FieldDefinition<TFrom, BsonValue> connectToField,
	AggregateExpressionDefinition<TIntermediate, BsonValue> startWith,
	FieldDefinition<BsonDocument, IEnumerable<BsonDocument>> as,
	FieldDefinition<BsonDocument, int> depthField = null
)

<ExtensionAttribute>
Public Shared Function GraphLookup(Of TInput, TIntermediate, TFrom) ( 
	pipeline As PipelineDefinition(Of TInput, TIntermediate),
	from As IMongoCollection(Of TFrom),
	connectFromField As FieldDefinition(Of TFrom, BsonValue),
	connectToField As FieldDefinition(Of TFrom, BsonValue),
	startWith As AggregateExpressionDefinition(Of TIntermediate, BsonValue),
	as As FieldDefinition(Of BsonDocument, IEnumerable(Of BsonDocument)),
	Optional depthField As FieldDefinition(Of BsonDocument, Integer) = Nothing
) As PipelineDefinition(Of TInput, BsonDocument)

[<ExtensionAttribute>]
static member GraphLookup : 
        pipeline : PipelineDefinition<'TInput, 'TIntermediate> * 
        from : IMongoCollection<'TFrom> * 
        connectFromField : FieldDefinition<'TFrom, BsonValue> * 
        connectToField : FieldDefinition<'TFrom, BsonValue> * 
        startWith : AggregateExpressionDefinition<'TIntermediate, BsonValue> * 
        as : FieldDefinition<BsonDocument, IEnumerable<BsonDocument>> * 
        ?depthField : FieldDefinition<BsonDocument, int> 
(* Defaults:
        let _depthField = defaultArg depthField null
*)
-> PipelineDefinition<'TInput, BsonDocument>