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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_ga_client_id(self):
 """ Retrieve the client ID from the Google Analytics cookie, if available, and save in the current session """

        request = self.get_ga_request()
        if not request or not hasattr(request, 'session'):
            return super(GARequestErrorReportingMixin, self).get_ga_client_id()
        if 'ga_client_id' not in request.session:
            client_id = self.ga_cookie_re.match(request.COOKIES.get('_ga', ''))
            client_id = client_id and client_id.group('cid') or str(uuid.uuid4())
            request.session['ga_client_id'] = client_id
        return request.session['ga_client_id']