title: How to fix warning about incompatible pointer types?
body: <p>I'm getting this warning:</p>
  
  <pre><code>Incompatible pointer types initializing 'NSMutableArray *__strong' with an expression of type 'NSArray *
  </code></pre>
  
  <p>This is the line of code giving the warning:</p>
  
  <pre><code>    NSMutableArray *apptDataArray = [AppointmentInfo MR_findAllWithPredicate:nsp];
  </code></pre>
  
  <p>where MR_findAllWithPredicate returns a NSArray.  I have been reading all of the postings in SO and Google, but found nothing like this.  I think it's fairly simple, but I need help.</p>