'Inject in a copy of the context the data requested to trigger the edit.
`content` and `rendered_content` is emptied.'

def _get_empty_context(self, context, instance, edit_fields, language, view_url, view_method, editmode=True):

    if (not language):
        language = get_language_from_request(context['request'])
    if ((not instance) and editmode):
        return context
    extra_context = copy(context)
    if (instance and isinstance(instance, Page)):
        if (edit_fields == 'titles'):
            edit_fields = 'title,page_title,menu_title'
        view_url = 'admin:cms_page_edit_title_fields'
    if (edit_fields == 'changelist'):
        view_url = ('admin:%s_%s_changelist' % (instance._meta.app_label, instance._meta.model_name))
    querystring = OrderedDict((('language', language),))
    if edit_fields:
        extra_context['edit_fields'] = edit_fields.strip().split(',')
    if self._is_editable(context.get('request', None)):
        extra_context.update(self._get_editable_context(extra_context, instance, language, edit_fields, view_method, view_url, querystring, editmode))
    extra_context['content'] = ''
    extra_context['rendered_content'] = ''
    return extra_context
