[graph-tool] Adding label to vertices

Hello, guys I have been learning graph-tool.. I would like to know if it is possible to create/load vertices and edges with labels. Im loading a graphml file, and in this file the node id = A, B ,C etc. However, when the loading is done, all vertex are transformed into numbers. I would like to know if is it possible to preservate the vertex name, such as A, B, C, "anyStrings", etc. Thanks in advance -- At.te Prof. Dr. Rafael S. Durelli. -- O conteúdo deste e-mail e anexos são restritos aos seus destinatários e de responsabilidade do remetente. O uso do e-mail deve estar de acordo com os regulamentos institucionais vigentes.