title: How to check valid Date() in Swift
body: <p>How to check if the date is valid, before making a SQL query  using</p>
  
  <pre><code>request.predicate = NSPredicate (format: "% @ &lt;= AND myDate% @&gt; = myDate" startDate, endDate)
  </code></pre>
  
  <p>an error occurs with the leap years, like 30 of February 2016.</p>
  
  <pre><code>// code form comment...
  let startDate:NSDate = dateFormatter.dateFromString("2016-10-01")!
  let endDate:NSDate = dateFormatter.dateFromString("2016-10-29")!
  </code></pre>