def addKeyword(self, keyword, weight):
        """
        add a relevant keyword to the topic page
        @param keyword: keyword or phrase to be added
        @param weight: importance of the provided keyword (typically in range 1 - 50)
        """
        assert isinstance(weight, (float, int)), "weight value has to be a positive or negative integer"
        self.topicPage["keywords"].append({"keyword": keyword, "wgt": weight})
add a relevant keyword to the topic page
        @param keyword: keyword or phrase to be added
        @param weight: importance of the provided keyword (typically in range 1 - 50)