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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 _get_auth_challenge(self, exc):
 """ Returns HttpResponse for the client. """

        response = HttpResponse(content=exc.content, status=exc.get_code_num())
        response['WWW-Authenticate'] = 'Basic realm="%s"' % REALM
        return response