title: 'Module' object is not callable
body: <p>I am new to python and django and having trouble doing a math function in my model.py file.</p>
  
  <pre><code>class Orders(models.Model):
    ...
    total = models.DecimalField(
                                max_digits = 6,
                                decimal_places = 2,
                                null = True,
                                blank = True,
                                )
    ...  
  
  
    def shipping(self):
        t = self.total
        ship_rate = 0.12
        return(t*ship_rate)
  </code></pre>
  
  <p>When I call it in a python shell   </p>
  
  <pre><code>dat = Orders.object.get(pk=12)
  dat.shipping()
  </code></pre>
  
  <p>Then I get the following error message:  </p>
  
  <pre><code>Traceback (most recent call last):
  File "&lt;console&gt;", line 1, in &lt;module&gt;
  File "C:\xx\xx\models.py", line 613, in shipping  
  ship_rate = 0.12  
  TypeError: 'module' object is not callable  
  </code></pre>
  
  <p>Can anyone see what I am doing wrong?</p>