title: MutableLiveData<String> to MutableLiveData<Int>
body: <p>How could I convert <code>MutableLiveData&lt; String&gt;</code> to <code>MutableLiveData&lt; Int&gt;</code>.</p>
  
  <pre><code> val text = NonNullMutableLiveData&lt;String&gt;("")
  </code></pre>
  
  <p>My <em>class NonNullMutableLiveData</em>:</p>
  
  <pre><code> class NonNullMutableLiveData&lt;T&gt;(private val defaultValue: T) :
          MutableLiveData&lt;T&gt;() {
          override fun getValue(): T {
              return super.getValue() ?: defaultValue
          }
      }
  </code></pre>
  
  <p>I would like to add another <code>MutableLiveData&lt;Int&gt;</code> in which I have transformed value of <code>MutableLiveData&lt;String&gt;</code></p>
  
  <p>Thanks</p>