def count(self, eventRegistry):
        """
        return the number of articles that match the criteria
        @param eventRegistry: instance of EventRegistry class. used to obtain the necessary data
        """
        self.setRequestedResult(RequestEventArticles(**self.queryParams))
        res = eventRegistry.execQuery(self)
        if "error" in res:
            print(res["error"])
        count = res.get(self.queryParams["eventUri"], {}).get("articles", {}).get("totalResults", 0)
        return count
return the number of articles that match the criteria
        @param eventRegistry: instance of EventRegistry class. used to obtain the necessary data