anchor.diff:              <| client 
               |> task
   
  -        member x.ListWithDocsAsync (?options): Task<ListResponse<'doctype>> =
  +        member x.ListWithDocsAsync ([<Optional; DefaultParameterValue(null)>] ?options): Task<ListResponse<'doctype>> =
               let opts = 
                   options 
                   |> Option.map listOptionsToFs
  
positive.code:             resp.DesignDocs <- Seq.ofList designDocs
              resp
  
          member __.GetAsync(id: string, ?rev: string): Task<'doctype> =
              client 
              |> get id rev
              |> Async.Map toDoc
              |> task
  
          member __.FindByExpressionAsync (exp, ?options): Task<IEnumerable<'doctype>> = 
              let opts = 
                  options 
                  |> Option.map findOptionsToFs 
  
negative.code:     open System.Threading.Tasks
      open System.Collections.Generic
      open Davenport.Csharp.Types
      open System.Runtime.InteropServices
  
      module ExpressionParser = 
          open System.Linq.Expressions
  