'Get a label for a node
@param node_id: the node ID
@param represent: the node ID representation method'

def label(self, node_id, represent=None):

    LABEL = 'l'
    theset = self.theset
    node = theset.get(node_id)
    if node:
        if (LABEL in node):
            label = node[LABEL]
        else:
            self._represent(node_ids=[node_id], renderer=represent)
        if (LABEL in node):
            label = node[LABEL]
        if (type(label) is unicode):
            try:
                label = label.encode('utf-8')
            except UnicodeEncodeError:
                pass
        return label
    return None
