Translate a select node into a latex qtree node.
        :param node: a treebrd node
        :return: a qtree subtree rooted at the node

def select(self, node):
        """
        Translate a select node into a latex qtree node.
        :param node: a treebrd node
        :return: a qtree subtree rooted at the node
        """
        child = self.translate(node.child)
        return '[.${op}_{{{conditions}}}$ {child} ]'\
            .format(op=latex_operator[node.operator],
                    conditions=node.conditions, child=child)