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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 redirect_params(url_name, params=None):
 """ Redirect to ``url_name`` with ``params`` as querystring :param unicode url_name: a URL pattern name :param params: Some parameter to append to the reversed URL :type params: :obj:`dict` or :obj:`NoneType<types.NoneType>` :return: A redirection to the URL with name ``url_name`` with ``params`` as querystring. :rtype: django.http.HttpResponseRedirect """

    url = reverse(url_name)
    params = urlencode(params if params else {})
    return HttpResponseRedirect(url + "?%s" % params)