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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 bad_request(request, template_name='400.html'):
 """ 400 error handler. Templates: :template:`400.html` Context: None """


    response = render_in_page(request, template_name)

    if response:
        return response

    try:
        template = loader.get_template(template_name)
    except TemplateDoesNotExist:
        return http.HttpResponseBadRequest('<h1>Bad Request (400)</h1>', content_type='text/html')
    return http.HttpResponseBadRequest(template.render(Context({})))