title: What does a colon after a tuple but before another type mean within a method signature?
body: <p>What does a colon that's positioned after a tuple but before another type mean within a method signature?</p>
  
  <p>Here's the syntax:</p>
  
  <pre><code>member this.Post (portalId : string, req : PushRequestDtr) : IHttpActionResult =
  </code></pre>
  
  <p>Here's the context:</p>
  
  <pre><code>type PushController (imp) =
      inherit ApiController ()
  
      member this.Post (portalId : string, req : PushRequestDtr) : IHttpActionResult =
          match imp req with
          | Success () -&gt; this.Ok () :&gt; _
          | Failure (ValidationFailure msg) -&gt; this.BadRequest msg :&gt; _
          | Failure (IntegrationFailure msg) -&gt;
              this.InternalServerError (InvalidOperationException msg) :&gt; _
  </code></pre>
  
  <p>Specifically, what does this method signature mean?</p>
  
  <p>Does this method take two parameters or one parameter?</p>
  
  <p>I understand this:</p>
  
  <pre><code>(portalId : string, req : PushRequestDtr)
  </code></pre>
  
  <p>But I'm confused about this syntax that's appended to the end of it:</p>
  
  <pre><code>: IHttpActionResult
  </code></pre>