title: How do i write an implicit Function conversion for a map call in Scala
body: <p>How do I write an implicit conversion for the code below (simplified)? I understand that you need to convert <code>(Int) =&gt; B</code> to <code>(String) =&gt; B</code>.</p>
  
  <pre><code>List(1, 2, 3).map { s: String =&gt; "_" + s }
  // expected: List("_1", "_2", "_3")
  </code></pre>