old_contents: from __future__ import absolute_import
  
  from cms.plugin_pool import plugin_pool
  from cms.plugin_base import CMSPluginBase
  
  from .models import AccordionHeader, Collapsible
  
  
  class AccordionHeaderPlugin(CMSPluginBase):
      model = AccordionHeader
      name = "Accordion Header"
      render_template = "cmsplugin_collapse/accordionheader.html"
      allow_children = True
      child_classes = ["CollapsiblePlugin"]
  
      def render(self, context, instance, placeholder):
          context.update({
              'instance': instance,
              })
          return context
  
  
  class CollapsiblePlugin(CMSPluginBase):
      model = Collapsible
      name = "Collapsible"
      render_template = "cmsplugin_collapse/accordioncollapsible.html"
      parent_classes = ["AccordionHeaderPlugin"]
      allow_children = True
  
      def render(self, context, instance, placeholder):
          context.update({
              'instance': instance,
              })
          return context
  
  plugin_pool.register_plugin(AccordionHeaderPlugin)
  plugin_pool.register_plugin(CollapsiblePlugin)
  
new_contents: from __future__ import absolute_import
  
  from cms.plugin_pool import plugin_pool
  from cms.plugin_base import CMSPluginBase
  
  from .models import AccordionHeader, Collapsible
  
  
  class AccordionHeaderPlugin(CMSPluginBase):
      model = AccordionHeader
      name = "Accordion Header"
      render_template = "cmsplugin_collapse/accordionheader.html"
      allow_children = True
      child_classes = ["CollapsiblePlugin"]
  
      def render(self, context, instance, placeholder):
          context.update({
              'instance': instance,
              })
          return context
  
  
  class CollapsiblePlugin(CMSPluginBase):
      model = Collapsible
      name = "Collapsible"
      render_template = "cmsplugin_collapse/accordioncollapsible.html"
      parent_classes = ["AccordionHeaderPlugin"]
      allow_children = True
  
      def render(self, context, instance, placeholder):
          context.update({
              'instance': instance,
              })
          return context
  
  
  plugin_pool.register_plugin(AccordionHeaderPlugin)
  plugin_pool.register_plugin(CollapsiblePlugin)
  
subject: Fix flake8 warning