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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def save_model(self, request, entry, form, change):
 """ Fill the content field with the interpretation of the placeholder """

        context = RequestContext(request)
        try:
            content = render_placeholder(entry.content_placeholder, context)
            entry.content = content or ''
        except KeyError:
            # https://github.com/django-blog-zinnia/cmsplugin-zinnia/pull/61
            entry.content = ''
        super(EntryPlaceholderAdmin, self).save_model(
            request, entry, form, change)