title: Django check if a related object exists error: RelatedObjectDoesNotExist
body: <p>I have a method <code>has_related_object</code> in my model that needs to check if a related object exists</p>
  <pre><code>class Business(base):
        name =  models.CharField(max_length=100, blank=True, null=True)
  
    def has_related_object(self):
          return (self.customers is not None) and (self.car is not None)
  
  
  class Customer(base):
        name =  models.CharField(max_length=100, blank=True, null=True)
        person = models.OneToOneField('Business', related_name=&quot;customer&quot;)
  </code></pre>
  <p>But I get the error:</p>
  <blockquote>
  <p>Business.has_related_object()</p>
  <p>RelatedObjectDoesNotExist: Business has no customer.</p>
  </blockquote>