# Exercise2.1 Error - cannot launch python node

**URL:** <https://get-help.theconstruct.ai/t/exercise2-1-error-cannot-launch-python-node/681>\
**Category:** ROS Basics In 5 Days (Python)\
**Tags:** error\
**Created:** [September 10, 2019, 8:04am UTC](https://get-help.theconstruct.ai/t/exercise2-1-error-cannot-launch-python-node/681 "2019-09-10T08:04:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jimohafeezco](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/jimohafeezco/32/10_2.png) [@jimohafeezco](https://get-help.theconstruct.ai/u/jimohafeezco)\
**Post date:** [September 10, 2019, 8:04am UTC](https://get-help.theconstruct.ai/t/exercise2-1-error-cannot-launch-python-node/681/1 "2019-09-10T08:04:58Z")

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ERROR: cannot launch node of type [exercise21/move\_robot.py]: can’t locate node [move\_robot.py] in package [exercise21]  
I have tried all possible best to solve it myself  
Below is the screenshot of how my directory looks.

 ![2](https://get-help.robotigniteacademy.com/uploads/default/original/1X/0ed1c60a3ac8efdebd6b8a68a4521dc9460fcc1d.png)  
Also i did not create launch and src folders initially but later did. Is it compulsory it is done.  
i did:  
source devel/setup.bash  
catkin\_make  
I used **roslaunch exercise21 move.launch** to run my file.

I do not know how it does not work for me. thanks

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<div class="post-metadata">

**Author:** ![bayodesegun](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/bayodesegun/32/10684_2.png) [@bayodesegun](https://get-help.theconstruct.ai/u/bayodesegun)\
**Post date:** [September 10, 2019, 10:33am UTC](https://get-help.theconstruct.ai/t/exercise2-1-error-cannot-launch-python-node/681/2 "2019-09-10T10:33:47Z")

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Hi @jimohafeezco,

Please check out the post below for the solution:

> **[ERROR: cannot launch node of type \[package/file.py\]: can't locate node...](https://get-help.theconstruct.ai/t/error-cannot-launch-node-of-type-package-file-py-cant-locate-node-file-py-in-package-package/54)**
>
> This error is very common when using ROS to launch a python node, either via rosrun or roslaunch. SOLUTION: Does the file file.py… exist in the package package? If not, create it! (Does the package itself exist and is it spelled correctly?)....