title: How can I use the actual datetime for a field in Odoo 11
body: <p>I want some like datetime.now() or similar in Odoo 11 to get the actual date and time. </p>
  
  <p>I tried the code I saw in another answers in stawoverflow, but doesn´t works for me. Can someone put an example for how to do it?</p>
  
  <p>Examples that doesn´t works: </p>
  
  <pre><code>exit = fields.Datetime('Date current action', required=False, readonly=False, select=True, default=lambda self: fields.datetime.now())
  
  exit = fields.Datetime(string="Date current action", default=lambda *a: datetime.now())
  
  exit= fields.Date.context_today(self, timestamp=datetime.datetime.now())
  </code></pre>