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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 ask_backend(self):
 """ Ask the user to choose the backend """

        response = self._ask_boolean(
            "Do you have a local docker daemon (on Linux), do you use docker-machine via a local machine, or do you use "
            "Docker for macOS?", True)
        if (response):
            self._display_info("If you use docker-machine on macOS, please see "
                               "http://inginious.readthedocs.io/en/latest/install_doc/troubleshooting.html")
            return "local"
        else:
            self._display_info(
                "You will have to run inginious-backend and inginious-agent yourself. Please run the commands without argument "
                "and/or read the documentation for more info")
            return self._display_question("Please enter the address of your backend")