title: What is the default value of django's model field options ``blank`` and ``null`` when they're not set?
body: <p>In the <a href="https://docs.djangoproject.com/en/1.10/ref/models/fields/" rel="noreferrer">documentation</a>, I was not able to find an answer to this.</p>
  
  <p>If I want a field to be left blank, do I have to explicitly set <code>blank=True</code> ?</p>
  
  <p>EDIT: I'm blind. Or stupid. Thanks for pointing that out to me ;)</p>