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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 initialize( self, region="us-west-1", host=None, port=8000, config_dir=None, session=None ):
 """ Set up the repl for execution. """

        try:
            import readline
            import rlcompleter
        except ImportError:
            # Windows doesn't have readline, so gracefully ignore.
            pass
        else:
            # Mac OS X readline compatibility from http://stackoverflow.com/a/7116997
            if "libedit" in readline.__doc__:
                readline.parse_and_bind("bind ^I rl_complete")
            else:
                readline.parse_and_bind("tab: complete")
            # Tab-complete names with a '-' in them
            delims = set(readline.get_completer_delims())
            if "-" in delims:
                delims.remove("-")
                readline.set_completer_delims("".join(delims))

        self._conf_dir = config_dir or os.path.join(
            os.environ.get("HOME", "."), ".config"
        )
        self.session = session or botocore.session.get_session()
        self.engine = FragmentEngine()
        self.engine.caution_callback = self.caution_callback
        if host is not None:
            self._local_endpoint = (host, port)
        self.engine.connect(
            region, session=self.session, host=host, port=port, is_secure=(host is None)
        )

        self.conf = self.load_config()
        for key, value in iteritems(DEFAULT_CONFIG):
            self.conf.setdefault(key, value)
        self.display = DISPLAYS[self.conf["display"]]
        self.throttle = TableLimits()
        self.throttle.load(self.conf["_throttle"])