OpenLayers bindTo is not a function
<p>I'm getting this error message when I try to bind view of the first map to the second map. So, I have two maps - mapOne and mapTwo. When I do not make any binding they are working nicely. However, when I slightly change declaration of mapTwo and add binding statement, I get that error message. This is a code I have.</p>

<pre><code>// Before. It works good.
var mapTwo = new ol.Map({
    target: obj,
    renderer: 'canvas',
    layers: layers,
    controls:[],
    view: view
});

//After. It does not work
var mapTwo = new ol.Map({
    target: obj,
    renderer: 'canvas',
    layers: layers,
    controls:[]
});

mapTwo.bindTo('view', mapOne);
</code></pre>

<p>So, what am I doing wrong here??</p>