Why dict.get return a tuple with None? : <p>I have a dict:</p>

<pre><code>book = {
'id': 2,
'author': 'J.R.R. Tolkien',
'pages': 332,
'title': 'Fellowship',
}

err_msg='No such key'

a = book.get('signature'),err_msg
print(a)
</code></pre>

<p>Result is:</p>

<blockquote>
  <p>(None, 'No such key')</p>
</blockquote>

<p>Why I receive the tuple as a result instead of 'No such key'?</p>

<p>In the documentation:</p>

<p><strong>get(key[, default])</strong></p>

<p><em>Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError.</em></p>
