text: from django import forms
  from django.template.loader import render_to_string
  from django.utils.safestring import mark_safe
  
  
  class FeedbackEditorFileWidget(forms.ClearableFileInput):
      """
      Clearable file widget.
  
      Can be made un-clearable (for required fields) using the
      ``clearable`` argument for ``__init__``.
      """
      template_name = 'devilry_gradingsystem/widgets/feedbackeditorfilewidget.django.html'
  
      def __init__(self, feedbackfile, attrs=None):
          self.feedbackfile = feedbackfile
          super(FeedbackEditorFileWidget, self).__init__(attrs)
  
      def render(self, name, value, attrs=None):
          attrs = attrs or {}
          input_html = forms.FileInput.render(self, name, value, attrs)
          output = render_to_string(self.template_name, {
              'input_html': input_html,
              'feedbackfile': self.feedbackfile,
              'clear_checkbox_name': self.clear_checkbox_name(name)
          })
          return mark_safe(output)
  