Does building a Python library fall in the category of research? If a Python library is built can it be turned into a research paper? Will it be accepted?
The point of research is the production of knowledge. If, after you take away all the code you’ve written and the datasets you’ve collected, there’s nothing left, then you’re not doing research, you’re doing development.

So, if you want to do artefact-oriented research like this, the question you have to ask yourself is this: what is the new knowledge you’re producing? Are you testing a new, better algorithm? Are you applying an existing algorithm in a new context and determining if it works there? Are you investigating how a complex system functions, or how it interacts with humans and/or the environment? What is the research question that you’re answering?

If you do determine that you’re doing research rather than development, however, there are a number of artefact-oriented research methodologies, such as the Design Science Research Methodology. You should be able to find more information on it with Google Scholar, if you’re a member of an institution that gives you access to their research journal subscriptions.