<span><span>(<span><span class="type-var">'i</span> list</span>, <span><span class="type-var">'o</span> list</span>, <span class="type-var">'err</span>)</span> <a href="index.html#type-validator">validator</a></span></code></dt><dd><p>Validate a list of items. Run the given validator for each item returning all the errors.</p><pre><code class="ml">let hobbie_validator =
  let open Validator in
  string_is_not_empty &quot;Must not be empty&quot;

let validator input =
  let open Validator in
  build build_