anchor.diff:  type PullRequestType =
   | Invalid of XUri
   | AutoMergeable of XUri
  +| UnknownMergeability of XUri
   | Skip
   
   [<DreamService(
  
positive.code:     let ClosePullRequest (prUri : XUri) =
          Plug.New(prUri)
              .Post(Json("""{ "state" : "closed"  }""", [| new KeyValuePair<_, _>("Authorization", "token " + token.Value); new KeyValuePair<_, _>("X-HTTP-Method-Override", "PATCH") |]))
  
      let MergePullRequest (prUri : XUri) =
          let mergePlug = Plug.New(prUri.At("merge"))
  
negative.code:         new DreamMessage(DreamStatus.Ok, new DreamHeaders(headers), MimeType.JSON, payload)
  
      let DeterminePullRequestType pr =
          let pullRequestUrl = pr?pull_request?url.AsString()
          if InvalidPullRequest pr then
              Invalid (new XUri(pullRequestUrl))
          else if UnknownMergeabilityPullRequest pr then
              UnknownMergeability (new XUri(pullRequestUrl))
          else if AutoMergeablePullRequest pr then
              AutoMergeable (new XUri(pullRequestUrl))
          else
              Skip
  
  