编写的.launch文件，执行的时候说Found the following, but they're either not files

编写的.launch文件，执行的时候说

Found the following, but they're either not files

然后我设置了权限
chmod 777 talker_listener.launch，不管里面写了什么都是报错：

/home/xmy/catkin_ws/src/basic/launch/talker_listener.launch: 行 1: 未预期的符号 `newline' 附近有语法错误
/home/xmy/catkin_ws/src/basic/launch/talker_listener.launch: 行 1: `<launch>'

launch问价如下：

<launch>
 <node name="talker" pkg="rospy_tutorials"
       type="talker.py" output="screen" />
 <node name="listener" pkg="rospy_tutorials"
       type="listener.py" output="screen" />
</launch>