# Exercise 4.3 import Age module error

**URL:** <https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310>\
**Category:** ROS Basics In 5 Days (Python)\
**Created:** [November 15, 2020, 1:38am UTC](https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310 "2020-11-15T01:38:26Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![hskramer](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/hskramer/32/3225_2.png) [@hskramer](https://get-help.theconstruct.ai/u/hskramer)\
**Post date:** [November 15, 2020, 1:38am UTC](https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310/1 "2020-11-15T01:38:26Z")

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I compiled successfully and rosmsg list | grep Age gives the proper output so does rosmsg Age it shows everything year, month, day all float32. I finally checked the solution and found my CMakeList.txt was exactly like that show in the solution. The package.xml was slightly different I kept the build\_depends, exec\_depends and build\_export\_depends all grouped together. The solution had the build\_depends followed by build\_export\_depends like:  
\<build\_export\_depends\>rospy\<build\_export\_depends\>  
\<exec\_depend\>rospy\<exec\_depend\>

I was surprised it didn’t work since rosmsg showed everything the tutorial showed, but import module error persisted even after changing package.xml. I know the order doesn’t really matter but tried anyway and I sourced devel/setup.bash after compile completed each time. During the entire exercise I received no errors until I launched the launch file, rosrun gives the same error as I expected, rosmsg output is all correct. The only thing I did was accidentally hit the green button at the top which I posted in another topic don’t know if that would cause a problem . Made sure names of everything were different. I’m still learning a lot and enjoying the course occasional problems are to be expected with a relatively new and what must be a complex website.

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**Author:** ![roalgoal](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/roalgoal/32/7280_2.png) [@roalgoal](https://get-help.theconstruct.ai/u/roalgoal)\
**Post date:** [November 16, 2020, 8:21am UTC](https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310/2 "2020-11-16T08:21:41Z")

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Try deleting your build/ and devel/ folders:

```
cd catkin_ws/
rm -rf build/
rm -rf devel/

```

If that doesn’t work, can you share what the error says? It sounds like something might be off with the node.

Rodrigo

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**Author:** ![hskramer](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/hskramer/32/3225_2.png) [@hskramer](https://get-help.theconstruct.ai/u/hskramer)\
**Post date:** [November 17, 2020, 12:59am UTC](https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310/3 "2020-11-17T00:59:05Z")

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Solved, I often tell friends and family that I learn more from my mistakes and solving system errors than I do from anything else and that was certainly true here. I know far more about messages, CMakeLists and package.xml than I ever would have had it worked the first time. Rodrigo’s suggestion was the crucial step needed to get back on track. I finally deleted everything and started from scratch.

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**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:** [January 18, 2021, 8:56am UTC](https://get-help.theconstruct.ai/t/exercise-4-3-import-age-module-error/6310/4 "2021-01-18T08:56:31Z")

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A post was split to a new topic: [Package and Age custom message not found](https://get-help.theconstruct.ai/t/package-and-age-custom-message-not-found/7706)