old_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.forms import widgets
  from django.forms.util import flatatt
  from django.utils.safestring import mark_safe
  
  
  class SelectMultipleField(widgets.SelectMultiple):
      """Multiple select widget ready for jQuery multiselect.js"""
  
      allow_multiple_selected = True
  
      def render(self, name, value, attrs=None, choices=()):
          rendered_attrs = {'class': 'select-multiple-field'}
          rendered_attrs.update(attrs)
          if value is None:
              value = []
  
          final_attrs = self.build_attrs(rendered_attrs, name=name)
          # output = [u'<select multiple="multiple"%s>' % flatatt(final_attrs)]
          output = ['<select multiple="multiple"{0}>'.format(flatatt(final_attrs))]
          options = self.render_options(choices, value)
          if options:
              output.append(options)
  
          output.append('</select>')
          return mark_safe('\n'.join(output))
  
new_contents: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.forms import widgets
  from django.forms.util import flatatt
  from django.utils.safestring import mark_safe
  
  try:
      from django.utils.html import format_html
  except ImportError:
      def format_html(format_string, *args, **kwargs):
          return format_string.format(*args, **kwargs)
  
  
  class SelectMultipleField(widgets.SelectMultiple):
      """Multiple select widget ready for jQuery multiselect.js"""
  
      allow_multiple_selected = True
  
      def render(self, name, value, attrs=None, choices=()):
          rendered_attrs = {'class': 'select-multiple-field'}
          rendered_attrs.update(attrs)
          if value is None:
              value = []
  
          final_attrs = self.build_attrs(rendered_attrs, name=name)
          # output = [u'<select multiple="multiple"%s>' % flatatt(final_attrs)]
          output = [format_html('<select multiple="multiple"{0}>',
                                flatatt(final_attrs))]
          options = self.render_options(choices, value)
          if options:
              output.append(options)
  
          output.append('</select>')
          return mark_safe('\n'.join(output))
  
subject: Use format_html if it is available, fallback for dj 1.4