def build_cmd(self, *args):
        '''adb command array
        For example:
            build_cmd("shell", "uptime") will get
            ["adb", "-s", "xx..", "-P", "5037", "shell", "uptime"]
        '''
        return [self.adb(), "-s", self.serial] + self.adb_host_port_options + list(args)
adb command array
        For example:
            build_cmd("shell", "uptime") will get
            ["adb", "-s", "xx..", "-P", "5037", "shell", "uptime"]