# KeyError: 'The identifier "astrocyte\_index\_post" could not be resolved.' **URL:** \ **Category:** Science, Projects, and Showcases\ **Created:** [25 October 2022 12:56 UTC](https://brian.discourse.group/t/keyerror-the-identifier-astrocyte-index-post-could-not-be-resolved/820 "2022-10-25T12:56:26Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![mstimberg](https://yyz2.discourse-cdn.com/free1/user_avatar/brian.discourse.group/mstimberg/32/11_2.png) [@mstimberg](https://brian.discourse.group/u/mstimberg)\ **Post date:** [26 October 2022 14:51 UTC](https://brian.discourse.group/t/keyerror-the-identifier-astrocyte-index-post-could-not-be-resolved/820/2 "2022-10-26T14:51:52Z")
Hi @amanforthepeople , it’s unfortunately impossible to help you with an overly general question like that (“keep running into some errors”). The code in the image seems to be from here: [comp-glia-book/example\_6\_COBA\_with\_astro.py at master · mdepitta/comp-glia-book · GitHub](https://github.com/mdepitta/comp-glia-book/blob/master/Ch18.Stimberg/code/example_6_COBA_with_astro.py) (BTW, there’s a cleaner version of the same code in the Brian documentation: [Example: example\_6\_COBA\_with\_astro — Brian 2 2.5.1 documentation](https://brian2.readthedocs.io/en/stable/examples/frompapers.Stimberg_et_al_2018.example_6_COBA_with_astro.html)), but that code should run correctly. The error message complains about a missing definition of `astrocyte_index` in the synaptic equations, but the above linked code contains that definition in `synapses_eqs`. So I guess you are running a different version of the code? Please be more specific and/or post some code (preferably as text surrounded by triple backtick quotes – see e.g. [Basic writing and formatting syntax - GitHub Docs](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#quoting-code) – and not as an image). Thanks! --- _[View the full topic](https://brian.discourse.group/t/keyerror-the-identifier-astrocyte-index-post-could-not-be-resolved/820)._