# conda switch between python versions ![](/files/W5mcVYHfple3JeMC6g3W) What is `rdkit` and `nb_conda_kernels`? I see you are switching to a virtual environment with different python version. Was it the trick to change kernels you mentioned during walk-thrus session? **Radek's explaination:** Yup, that’s it. Essentially, how to have one conda env but multiple python versions. You can have one nb running python 3.5, and another python 3.7. Very rarely is this useful, but in the scenario where you want to run some old python code, there is a solution without having to set up a new environment. (also, if you have two envs and want to work on the code at the same time or execute files in succession – for instance to process some data in one notebook and continue in the other --, it gets painful… this is just a cleaner way to achieve it, though it is a super rare case that this might be needed) `rdkit` is just some random repo I wanted to use for a Kaggle competition, not sure I will use it ever again in my life**.** In fact, this is such a niche case I don’t even think it is worth covering this in the walk-thrus, but probably good to know this solution exists if you ever encounter a situation where it might be helpful (googling for this is not that easy). Bookmark for conversation: {% embed url="" %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://til.kurianbenoy.com/python/conda-switch-between-python-versions.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.