title: Create a mix of string and digit with Factory Boy in django
body: <p>I want to create a mix of string and digits like this: "XL1A" or "PP25" for one field in my database.How can I do that? I'm using only uppercase letter for now. </p>
  
  <pre><code>class CardFactory(DjangoModelFactory):
      class Meta:
          model = Card
      serial_number = FuzzyText(length=4, chars=string.ascii_uppercase)
  </code></pre>
  
  <p>Also, is there anyway to create random pattern rules for FuzzX in Factory Boy such as random IP addresses?</p>