def default_value(self):
    if self.auto_current_user or self.auto_current_user_add:
      return users.get_current_user()
    return None
Get key of reference rather than reference itself.
dataset/ETHPy150Open CollabQ/CollabQ/.google_appengine/google/appengine/ext/db/__init__.py/UserProperty.default_value--crossover with--dataset/ETHPy150Open CollabQ/CollabQ/.google_appengine/google/appengine/ext/db/__init__.py/ReferenceProperty.get_value_for_datastore