old_contents: from crispy_forms.helper import FormHelper
  from crispy_forms.layout import *
  from crispy_forms.bootstrap import *
  from crispy_forms.utils import render_field, flatatt
  
  from crispy_forms import layout
  
  class Fieldset(layout.Fieldset):
      template = "admin/fieldset.html"
  
  class Row(layout.Div):
  
      def __init__(self, *fields, **kwargs):
          css_class = 'form-row num%d' % len(fields)
          super(Row, self).__init__(css_class=css_class, *fields, **kwargs)
  
  class Col(layout.Column):
  
      def __init__(self, id, *fields, **kwargs):
          css_class = ['form-column', id, 'span%d' % kwargs.get('span', 6)]
          if kwargs.get('horizontal'):
              css_class.append('form-horizontal')
          super(Col, self).__init__(css_class=' '.join(css_class), *fields, **kwargs)
  
  class Main(layout.Column):
      css_class = "form-column main span9 form-horizontal"
  
  class Side(layout.Column):
      css_class = "form-column sidebar span3"
  
  class Container(layout.Div):
      css_class = "form-container row-fluid"
new_contents: from crispy_forms.helper import FormHelper
  from crispy_forms.layout import *
  from crispy_forms.bootstrap import *
  from crispy_forms.utils import render_field, flatatt
  
  from crispy_forms import layout
  
  class Fieldset(layout.Fieldset):
      template = "admin/fieldset.html"
  
  class Row(layout.Div):
  
      def __init__(self, *fields, **kwargs):
          css_class = 'form-row num%d' % len(fields)
          super(Row, self).__init__(css_class=css_class, *fields, **kwargs)
  
  class Col(layout.Column):
  
      def __init__(self, id, *fields, **kwargs):
          css_class = ['column', 'form-column', id, 'span%d' % kwargs.get('span', 6)]
          if kwargs.get('horizontal'):
              css_class.append('form-horizontal')
          super(Col, self).__init__(css_class=' '.join(css_class), *fields, **kwargs)
  
  class Main(layout.Column):
      css_class = "column form-column main span9 form-horizontal"
  
  class Side(layout.Column):
      css_class = "column form-column sidebar span3"
  
  class Container(layout.Div):
      css_class = "form-container row-fluid"
subject: add column class