title: Swift allSatisfy allow 'Enter' or New Line
body: <p>I have the following extension.</p>
  <pre><code>extension StringProtocol {
      func isLetterDigit(allowChars: String) -&gt; Bool {
          allSatisfy(&quot;\(allowChars)&quot;.contains)
      }
  }
  </code></pre>
  <p>I am using it like so:</p>
  <pre><code>if (!bioTextView.text!.isLetterDigit(allowChars: self.allowChars)) {
      displaySnackbar(messageString: &quot;Remove special characters in your bio&quot;)
  }
  </code></pre>
  <p><code>bioTextView</code> is a UITextView where I will allow users to use the enter key is they wish.</p>
  <p>My allowChars is the following</p>
  <pre><code>var allowChars: String = &quot;abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 .',!:&quot;
  </code></pre>
  <p>How can I allow the enter key/new line?</p>