terrain command parser

def cmd_terrain(self, args):
        '''terrain command parser'''
        usage = "usage: terrain <set|status|check>"
        if len(args) == 0:
            print(usage)
            return
        if args[0] == "status":
            print("blocks_sent: %u requests_received: %u" % (
                self.blocks_sent,
                self.requests_received))
        elif args[0] == "set":
            self.terrain_settings.command(args[1:])
        elif args[0] == "check":
            self.cmd_terrain_check(args[1:])
        else:
            print(usage)