title: F# - Sorting a list of string tuple
body: <p>Ex.</p>
  <blockquote>
  <p>sortPairs [(&quot;Derek&quot;, &quot;Christopher&quot;)]
  val it : (string * string) list = [(&quot;Christopher&quot;, &quot;Derek&quot;)]</p>
  </blockquote>
  <blockquote>
  <p>sortPairs [(&quot;Parker&quot;, &quot;Derek&quot;); (&quot;dora&quot;, &quot;derek&quot;)]
  val it : (string * string) list = [(&quot;derek&quot;; &quot;dora&quot;); (&quot;Derek&quot;, &quot;Parker&quot;)]</p>
  </blockquote>