title: Django ORM .values() not works properly
body: <p>This code dos not work:</p>
  
  <pre><code>analyzer_signs = Sign.objects.filter(is_analyzer_used=True).values('code', 'name')
  for analyzer_sign in analyzer_signs:
      print(analyzer_sign)
  </code></pre>
  
  <p>It prints nothing (doesn't enter the cycle)</p>
  
  <p>But when I delete <code>.values('code', 'name')</code> - It works greate:</p>
  
  <pre><code>analyzer_signs = Sign.objects.filter(is_analyzer_used=True)
  for analyzer_sign in analyzer_signs:
      print(analyzer_sign)
  </code></pre>
  
  <p>And I even can print text from fields <strong>code</strong> and <strong>name</strong>.</p>
  
  <p>I don't know what's going on. And no one of my teammates doesn't.
  Please, help!</p>
  
  <p>Here is the model code:</p>
  
  <pre><code>class ShortNameMixin(models.Model):
      short_name = models.TextField(blank=True)
  
      class Meta:
          abstract = True  #
  
  class CodeMixin(models.Model):
      code = models.CharField(max_length=125)
  
      class Meta:
          abstract = True
  
  class AbstractBaseItem(common_models.CommonInfoAutoIncrementPK):
      name = models.TextField()
      is_active = models.BooleanField(default=True)
  
      class Meta:
          abstract = True
  
      def __str__(self):
          return self.name
  
  class SimpleDirectoryItem(ShortNameMixin, CodeMixin, AbstractBaseItem):
  
      class Meta:
          abstract = True
  
  class Sign(SimpleDirectoryItem):
      additional_code = models.CharField(max_length=255, null=True, blank=True)
  ....
      is_analyzer_used = models.BooleanField(default=False)
  
      alias = 'it-is-allias'
  
      class Meta:
          db_table = 'signtable'
          unique_together = ('sign_type', 'name',)
          ordering = default_ordering
          default_permissions = ()
          permissions = (.......)
  </code></pre>
  
  <p>PS: I tried to install differents db dumps, launched this project on Linux Mint (virtualbox) and Windows - still not works! But my teammates says "It works on my machine"... Can you suppose, what the problem is? Any help!</p>