def METHOD_NAME(self, args):
    '''graph command'''
    if len(args) == 0:
        # list current graphs
        for i in range(len(self.graphs)):
            print("Graph %u: %s" % (i, self.graphs[i].fields))
        return
    elif args[0] == "help":
        print("graph <timespan|tickresolution|expression>")
    elif args[0] == "timespan":
        if len(args) == 1:
            print("timespan: %.1f" % self.timespan)
            return
        self.timespan = float(args[1])
    elif args[0] == "tickresolution":
        if len(args) == 1:
            print("tickresolution: %.1f" % self.tickresolution)
            return
        self.tickresolution = float(args[1])
    elif args[0] == "legend":
        self.cmd_legend(args[1:])
    else:
        # start a new graph
        self.graphs.append(Graph(self, args[:]))