title: Python regex for integer?
body: <p>I'm learning regex and I would like to use a regular expression in Python to define only integers - whole numbers but not decimals.</p>
  
  <p>I could make one that only allows numbers by using <code>\d</code>, but it also allows decimal numbers, which I don't want:</p>
  
  <pre><code>price = TextField(_('Price'), [
      validators.Regexp('\d', message=_('This is not an integer number, please see the example and try again')),
      validators.Optional()]) 
  </code></pre>
  
  <p>How can I change the code to <strong>only</strong> allow integers?</p>