anchor.diff:              |> Async.MapSeq toDoc 
               |> task
   
  -        member __.FindBySelectorAsync (dict, [<Optional; DefaultParameterValue(null)>] ?options): Task<IEnumerable<'doctype>> = 
  +        member __.FindBySelectorAsync (dict, [<Optional; DefaultParameterValue(null)>] ?options: FindOptions): Task<IEnumerable<'doctype>> = 
               let opts = 
                   options 
                   |> Option.map findOptionsToFs
  
positive.code:             |> Async.Map toDoc
              |> task
  
          member __.FindByExpressionAsync (exp, [<Optional; DefaultParameterValue(null)>] ?options): Task<IEnumerable<'doctype>> = 
              let opts = 
                  options 
                  |> Option.map findOptionsToFs 
  
negative.code:             <| client
              |> task
  
          member __.ExistsByExpressionAsync (exp: Linq.Expressions.Expression<Func<'doctype, bool>>): Task<bool> = 
              exp 
              |> ExpressionParser.parse
              |> existsBySelector
  