docs: def get_or_create(cls, key, defaults={}):
          '''
          A port of functionality from the Django ORM. Defaults can be passed in
          if creating a new document is necessary. Keyword args are used to
          lookup the document. Returns a tuple of (object, created), where object
          is the retrieved or created object and created is a boolean specifying
          whether a new object was created.
          '''
          instance = cls.get(key)
          if not instance:
              created = True
              data = dict(key=key)
              data.update(defaults)
              # Do an upsert here instead of a straight create to avoid a race
              # condition with another instance creating the same record at
              # nearly the same time.
              instance = cls.update(data, data, upsert=True)
          else:
              created = False
          return instance, created