type Wraped<'a> = { Payload: 'a }
type Model = { Name: string }

let dbTable = 
  [ { Payload = { Name = "1" } }
    { Payload = { Name = "2" } }
    { Payload = { Name = "3" } }
    { Payload = { Name = "4" } } ]

module Mongo =

    let getCollection<'a>(): 'a seq =
      match typeof<'a> with
      | t when t = typeof<Model> -> dbTable |> Seq.map (fun x -> unbox x.Payload)
      | _ -> failwith "no such table"
      
    let getWrappedCollection<'a>(): Wraped<'a> seq =
      match typeof<'a> with
      | t when t = typeof<Model> -> dbTable |> Seq.map (fun x -> unbox x)
      | _ -> failwith "no such table"
 
  

let collection: Model seq = Mongo.getCollection<Model>()
let collectionW: Wraped<Model> seq = Mongo.getWrappedCollection<Model>()

let item: Model = Seq.head collection

x.GetCollection<'a>() =     db.GetCollection<QueueEntry<'a>>(typeof<'a>.Name + "_queue")