Why is should.be.type() failing with "TypeError: (intermediate value).should.be.type is not a function"
<p>I do not understand why the following test is failing with the error:</p>

<blockquote>
  <p>TypeError: (intermediate value).should.be.type is not a function</p>
</blockquote>

<pre><code>describe('#Option object', function() {
    it('returns value as whatever type was passed to the constructor', function() {
        var o = function() {
            this.getValue = function() {
                return new Date();
            }
        };

        var i = new o();
        i.getValue().should.be.type('Date');
    })
});
</code></pre>

<p>I've read [most] of the <a href="http://shouldjs.github.io" rel="nofollow">Should.js documentation</a> but I must be missing something. Can anyone tell me what is wrong with my test?</p>