code: def build_attrs(self, *args, **kwargs):
          
          self.attrs.setdefault('data-minimum-input-length', 1)
          self.attrs.setdefault('data-tags', 'true')
          self.attrs.setdefault('data-token-separators', '[",", " "]')
          return super(Select2TagMixin, self).build_attrs(*args, **kwargs)
docs: Add select2's tag attributes.