Sets the span for the term from list of ids
        @type span_list: []
        @param span_list: list of wf ids forming span

def set_span_from_ids(self, span_list):
        """
        Sets the span for the term from list of ids
        @type span_list: []
        @param span_list: list of wf ids forming span
        """
        this_span = Cspan()
        this_span.create_from_ids(span_list)
        self.node.append(this_span.get_node())