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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 on_get(self, req, resp, handler=None, **kwargs):
 """Respond on GET HTTP request assuming resource retrieval flow. This request handler assumes that GET requests are associated with single resource instance retrieval. Thus default flow for such requests is: * Retrieve single resource instance of prepare its representation by calling retrieve method handler. Args: req (falcon.Request):
 request object instance. resp (falcon.Response):
 response object instance to be modified handler (method):
 list method handler to be called. Defaults to ``self.list``. **kwargs: additional keyword arguments retrieved from url template. """

        self.handle(
            handler or self.retrieve, req, resp, **kwargs
        )